Skin color variations were caused by:

a). The change in melanin, the skin's brown pigment

b). The climate of where people migrated to

c)Diets that are rich in Vitamin D

d) All of the above

Answers

Answer 1

I'm certain the answer is D: All of the above, but please correct me if I'm wrong ^^


Related Questions

The fertilization in __________happens outside the female's body​

Answers

Answer:

Frogs

Explanation:

Answer:

Hello there! I'm assuming frog and or dog :)

Which factors play a role in creating ocean waves?

Choose all answers that are correct.


wind duration

wind speed

wind change

wind elevation

wind direction

wind fetch

Answers

Answer:

1. Wind speed

2. Wind change

3. Wind elevation

4. Wind direction

Answer:

For k12 its::

Explanation:

wind direction

wind speed

wind fetch

wind duration

Yw guys! ^^

Explain why NO is more soluble in water than either N2 or O2. Fill in the following blanks.

a. Compared to nitrogen, the ____________of ethylene makes it more soluble in water.
b. The high solubility of sulfur dioxide can be explained by its ______________
c. Nitric oxide is more soluble than nitrogen and oxygen because of its ______________
d. Compared to oxygen, nitrogen's _____________ makes it more difficult for water molecules to surround the nitrogen molecules.

1. Polarity
2. Ability to react with water
3. Shorter bond length
4. Larger molecular size

Answers

Answer:

a. Larger molecular size

b. Ability to react with water

c. Polarity

d. Shorter bond length

Explanation:

Ethene is a larger molecule than oxygen and nitrogen hence it is more soluble than the both other gases .

SO2 dissolves readily in water to yield an acid solution. It is an acid anhydride.

Nitric oxide is a polar compound. It remains very much polar while nitrogen and oxygen are non polar.

Nitrogen is sp hybrized, this leads to a very short bond and does not easily interact with oxygen and nitrogen

Stoichiometric relationship

1. How many moles of oxygen will be produced from the decomposition of 3 moles of KCIO3?

Answers

Balanced Equation: 2 KCIO3 ⇒ 2 KCl + 3 O2

3 mol KClO3 x [tex]\frac{3 mol O2}{2 mol KClO3}[/tex] = 4.5 mol O2

Please answer ASAP! thanks

Answers

The answer is g your welcome

WILL MARK BRAINLIST
If a car travels 60 miles for two hours, what is the average speed?
15 mi/hr
30 mi/hr
45 mi/hr
60 mi/hr

Answers

Answer:

The average speed must be 30mph so this means the car traveled for 2hrs 60/30

Kinematics equations are used only by physicists and people who work in
space.
A. True
B. False

Answers

Answer:

FALSE

Explanation:

false. kinematics equations are used for many purposes.it is used to drive equations and to find the motion of an object. but it is used more in physics rather than maths.

answer is correct. :)

Complex ___ of ETC, which mediates transfer of electrons from succinate (FADH2) to UQ, is not a proton pump.

Answers

Answer:

Complex II

Explanation:

Complex II does not directly pump protons but rather sends two protons on to Complex III in the form of the reduced UQ known as ubiquinol.

Thus, the correct answer is Complex II

How has the United States government tried to preserve water sources?

Answers

Answer:

Implement rainwater harvesting systems to collect and store rainwater for drinking or recharging underground aquifers. Build wells to extract groundwater from underground aquifers. Provide home water-treatment capability through the use of filters, solar disinfection, or flocculants, to make drinking water safe.

Explanation:

the government of the United States preserves water sources by making waste water treatment and preventing water pollution

Steam is collected and observed to condense into liquid water. Which of the following would you expect to observe if a thermometer recorded the temperature of the substance?

SELECT AN ANSWER

The temperature would decrease.


The temperature would remain the same.


It would depend on the amount of steam.


The temperature would increase.

Answers

the water will be increased

Calculate the mass, in grams, of 912 atoms of iron, Fe (1 mol of Fe
has a mass of 55.85 g).

Answers

Answer:

8.45 × 10⁻²⁰ g

Explanation:

Step 1: Given data

Number of atoms of Fe (N): 912 atomsMolar mass of Fe (M): 55.85 g/mol

Step 2: Calculate the mass, in grams, of 1 atom of Fe

We will use Avogadro's number: there are 6.02 × 10²³ atoms of Fe in 1 mole of Fe.

55.85 g/mol × 1 mol/6.02 × 10²³ atom = 9.27 × 10⁻²³ g/atom

Step 3: Calculate the mass corresponding to 912 atoms

9.27 × 10⁻²³ g/atom × 912 atom = 8.45 × 10⁻²⁰ g

This is the chemical formula for Chormium (III) nitrate Cr(NO3)3Calculate the mass percent of nitrogen in chromium(III) nitrate.

Answers

Answer:

The percent composition for nitrogen in chromium(III) nitrate is 6%.

Explanation:

The mass percent of nitrogen in chromium(III) nitrate is 17.655%.

Calculation,

Molar mass of one oxygen = 16 g

molar mass of nine oxygen = 9 × 16 g = 144 g

molar mass of one nitrogen atom = 14 g

molar mass of three nitrogen atom = 3 × 14 g = 42 g

molar mass of one chromium atom = 51.99 g

molar mass of chromium (III) nitrate molecule = 144 g + 42 g + 51.99 g = 237.99 g

Mass percent of nitrogen = mass of three nitrogen atom× 100 /mass of chromium(III)nitrate

Mass percent of nitrogen = 42 g/237.99 g × 100 = 17.655%

What is mass percentage?

The percentage of the mass of the element or solute divided by the mass of the compound or solute is called mass percentage

learn about mass percentage,

https://brainly.com/question/16885872

#SPJ2

I need help explaining what are the differences between Solids, Liquids, and Gases.

Answers

Explanation: solids are frozen like if you freeze tea it becomes a solid , liquids is like tea and gases is like when you boil water and it becomes a gas

The following table lists molecular weight data for a polypropylene material. Molecular Weight Range (g/mol) xi wi
8,000 - 16,000 0.07 0.03 16,000 - 24,000 0.15 0.09 24,000 - 32,000 0.26 0.21 32,000 - 40,000 0.27 0.27 40,000 - 48,000 0.18 0.28 48,000 - 56,000 0.07 0.12
Click here to access Table 14.3. Atomic weights for several elements are included in the following table: Carbon 12.01 g/mol Chlorine 35.45 g/mol Fluorine 19.00 g/mol Hydrogen 1.008 g/mol Oxygen 16.00 g/mol Nitrogen 14.01 g/mol Compute the following:
(a) the number-average molecular weight, Enter your answer for part (a) in accordance to the question statement g/mol
(b) the weight-average molecular weight, Enter your answer for part (b) in accordance to the question statement g/mol
(c) the degree of polymerization.

Answers

Answer:

a) the number-average molecular weight is 32,400 g/mol

b) the weight-average molecular weight is 36,320 g/mol

c) the degree of polymerization is 770

Explanation:

Given the data in the question;

Molecular                  Mean        Number      Weight      Number        Weight

weight                                                                             average         average

(g/mol)                    Mi(g/mol)         xi                wi          xiMi                  wiMi

8,000-16,000            12,000        0.07           0.03         840                360

16,000-24,000          20,000       0.15           0.09         3000              1800

24,000-32,000         28,000       0.26           0.21          7280              5880

32,000-40,000         36,000       0.27           0.27         9720               9720

40,000-48,000         44,000       0.18            0.28         7920              12320

48,000-56,000         52,000       0.07           0.12          3640              6240

∑                                                                                Mn=32,400     Mw=36,320

so;

a)  the number-average molecular weight

Mn = ∑Mixi

so from the table above; summation of Row Mixi

Mn = ∑Mixi = 32,400

Therefore, the number-average molecular weight is 32,400 g/mol

b) the weight-average molecular weight

Mw = ∑Miwi

so from the table above; summation of Row Miwi

Mw = ∑Miwi = 36,320

Therefore, the weight-average molecular weight is 36,320 g/mol

c) the degree of polymerization

the degree of polymerization of polypropylene can be determined using number-average molecular and repeat unit molecular weight.

now, for polypropylene { CH₂ = CH - CH₃ }

the repeat unit consist of 3 carbon atoms and 6 hydrogen atoms

given that;

Atomic weight of Carbon mC = 12.01 g/mol and

Atomic weight of  Hydrogen mH = 1.008 g/mol

now we find the repeat unit molecular weight of polypropylene

m = nCmC + nHmH

where n is the number of repeat of atoms

so we substitute

m = ( 3 × 12.01) + ( 6 × 1.008)

m = 36.03 + 6.048

m = 42.078 g/mol

now we calculate the degree of polymerization;

DP = Mn / m

so we substitute

DP = 32,400 / 42.078

DP = 769.9985 ≈ 770

Therefore,  the degree of polymerization is 770

If the mercury in a manometer raises 30.0 millimeters due to a change in pressure, what is the corresponding change in pressure in atm?

Answers

Answer:

0.03947 atm

Explanation:

The relationship between mmHg and atm is given as;

1 atm = 760 mmHg

x atm = 30 mmHg

Upon solving for x;

x * 760 = 30 * 1

x = 30 / 760 = 0.03947 atm

Which word best describes the relationship between polyps and algae
exoskeletal
Bleached
Photosynthetic
Symbiotic

Answers

Answer:

symbiotic

Explanation:

There like a close friendship

1
What is the name of Ba3(PO4)2?
O a. Tribarium Diphosphate
tof
O b. Triboron Diphosphate
O c. Boron Phosphate
O d. Barium Phosphate

Answers

Answer:

The answer is barium phosphate

Question 6 of 25
When nonionizing radiation is absorbed by matter, it usually becomes which
type of energy?
A. Thermal
B. Mechanical
C. Electromagnetic
O D. Chemical

Answers

Answer:

thermal

Explanation:

a p e x


A car changes its velocity from 0 m/s to 14 m/s in 2 seconds.
What is the acceleration

Answers

Answer:

7

Explanation:

You divide the 14m/s by 2 and get the answer of the acceleration of 7

What is the functional groups of CH3CH2CH(OH)CH2C(CH3)2Br?​

Answers

Answer:

What is the functional groups of CH3CH2CH(OH)CH2C(CH3)2Br?

explain why the definition of philosophy as the love of wisdom in insufficient?​

Answers

Answer:

The word “philosophy” literally means the “love” (philo in Greek) of “wisdom” (sophia). So, a philosopher is somebody who loves wisdom. This, of course, leaves us with 2 important questions: What is wisdom? And what does it mean to love wisdom?

The idea of philosophy goes all the way back to ancient Greece. It is said that the philosopher Pythagoras in the 6th century BCE was the 1st to call himself a philosopher—a philosophos, or “lover of wisdom.” In calling himself this, he was not claiming to be wise. Instead, he was merely saying that he was somebody who valued or cherished wisdom.

Later, the philosopher Plato, who lived in the 5th century BCE, explored these ideas in more depth. In a text called the Symposium, Plato claimed that a philosopher was somebody who was “between the wise and the ignorant.” In other words, a philosopher cared about wisdom but also knew that they were ignorant (we will see tomorrow how Plato was influenced in this by his teacher, Socrates).

Explanation:

Fred is about to order a stack of four pancakes with butter and syrup, but he wonders how much he would need to exercise to burn off the Calories from it. He pulls out his cell phone and finds the nutritional information for the stack of pancakes. He notes that a serving has 181g of carbohydrates, 27g of fat, and 16g of protein. Now, he has to convert these values into Calories.

Running at a pace of 8 minutes per mile burns 14 Calories/minute. How many minutes would he have to run at an 8 minutes per mile pace to bum off the Calories from the stack of pancakes?

Answers

Answer:

The correct answer is - 73.64 minutes.

Explanation:

We know that each gram of protein and carbohydrate produces 4 calories of energy whereas fat produces 9 cal energy per gram.

So, the Calories from carbohydrates

= 181 ×4

= 724 Cal

and, 27 g fat produces = 27 × 9 = 243 Cal

and, 16 g protien = 16 × 4 = 64 Cal

so the total energy will be - 243+ 724+ 64 = 1031 Cal

Thus, the time Fred need to run = 1031/14 =73.64 min

Explain how the Octet Rule would say that the elements of potassium and chlorine would react.

Answers

Answer:

The octet rule is only applicable to the main group elements. The molecules of the halogens, oxygen, nitrogen, and carbon are known to obey the octet rule. In general, the elements that obey this rule include the s-block elements and the p-block elements (except hydrogen, helium, and lithium).

Explanation:

I hope this helps and pls mark me brainliest :)

Look at sample problem 19.10 in the 8th ed Silberberg book. Write the Ksp expression. Find the concentrations of the ions you need (in this case Ca2 and F-). Put those concentrations into the Ksp expression to calculate Q. Compare Q to K A common laboratory method for preparing a precipitate is to mix solutions containing the component ions. Does a precipitate form when 10. ml of 0.0010 M Ca(NO3)2 is mixed with 10. ml of 0.00010 M NaF

Answers

Answer:

Explanation:

From the information given:

[tex]CaF_2 \to Ca^{2+} + 2F^-[/tex]

[tex]Ksp = 3.2 \times 10^{-11}[/tex]

no of moles of [tex]Ca^{2+}[/tex] = 0.01 L × 0.0010 mol/L

no of moles of [tex]Ca^{2+}[/tex] = [tex]1 \times 10^{-5} \ mol[/tex]

no of moles of [tex]F^-[/tex] = 0.01 L × 0.00010 mol/L

no of moles of [tex]F^-[/tex] = [tex]1 \times 10^{-6}\ mol[/tex]

Total volume = 0.02 L

[tex][Ca^{2+}}] = \dfrac{1\times10^{-5} \ mol}{0.02 \ L} \\ \\ \\ \[[Ca^{2+}}] = 0.0005 \ mol/L[/tex]

[tex][F^{-}] = \dfrac{(1\times 10^{-6} \ mol)}{0.02 \ L}[/tex]

[tex][F^{-}] = 5 \times 10^{-5} \ mol/L[/tex]

[tex]Q = [Ca^{2+}][F^-]^2 \\ \\ Q = 0.0005 \times (5\times 10^{-5})^2 \\ \\ Q = 1.25 \times 10^{-12}[/tex]

Since Q<ksp, then there will no be any precipitation of CaF2

The 50:50 mixture of aspirin (Lit. MP: 135-136 oC) and 4-bromobenzoic acid (Lit. MP: 252-254 oC) will have the melting point in the range of:______.

Answers

Answer:

193.5-195 °C.

Explanation:

Hello!

In this case, since the mixture is 50:50, we can infer that an average may be used to compute the required range; thus, we first compute the the inner limit by using 135 °C and 252 °C:

[tex]\frac{135+252}{2} =193.5\°C[/tex]

And the upper limit:

[tex]\frac{136+254}{2} =195\°C[/tex]

Thus, the average melting point would be around 193.5-195 °C.

Best regards!

Titanium(IV) chloride decomposes to form titanium and chlorine, like this:

TiCl4(l) → Ti(s)+ 2Cl2(g)

At a certain temperature, a chemist finds that a reaction vessel containing a mixture of titanium(IV) chloride, titanium, and chlorine at equilibrium has the following composition:

Compound Amount
TiCl4 4.18g
Ti 1.32g
Cl2 1.08g

Required:
Calculate the value of the equilibrium constant for this reaction.

Answers

The full question is shown in the image attached to this answer

Answer:

6.2 * 10^-3

Explanation:

The reaction at equilibrium is as follows;

TiCl4(l) → Ti(s)+ 2Cl2(g)

We have to obtain the concentration of chlorine gas as follows;

[Cl2] = 1.08/70.91 g/mol × 5.2 L

[Cl2] = 0.079 M

Kc = [Cl2]^2

Kc = [ 0.079]^2

Kc = 6.2 * 10^-3

Which statement best describes a heart attack?

A. The heart muscle tissues get too much oxygen

B. The heart muscle tissue get too little oxygen

C. The heart muscle tissue get the normal average amount of oxygen

D. None of the above

Answers

B the heart muscle gets too little oxygen

Answer:

D

Explanation:

How can we solve food insecurity while reducing food waste?
o inventory food supplies to avoid overbuying
O donate unused food to food banks
O purchase only as much food as you need
O don't throw scraps in the landfill

Answers

Answer:

donate unused food to food banks

Explanation:

Becuse food banks processes food to make very fine particles which is mixed with soil and can be given to the plants

Calculate the volume in mL of 0.100 of CaCl2 needed to produce 1.00 g of CaCO3. there is an excess of Na2CO3

Answers

Answer:

100. mL

Explanation:

The computation of the volume in mL is shown below:

The balance equation of the double displacement reaction is

[tex]CaCl_{2} + Na_{2}CO_{3} \rightarrow 2 NaCl + CaCO_{3}[/tex]

Now determine the moles that corresponding to 1.00 g of CaCO₃

As,

The molar mass of CaCO₃ is 100.09 g/mol.

So,

= 1.00 g × 1 mol/100.09 g

= 0.0100 mol

Now

the moles of CaCl₂ needed to generate 0.0100 moles of CaCO₃

As we know that

The molar ratio of CaCl₂ to CaCO₃ is 1:1.

So, The moles of CaCl₂ needed is

=  1 ÷ 1 × 0.0100 mol

= 0.0100 mol.

Now volume of 0.100 M CaCl₂ that contains 0.0100 mol is  

= 0.0100 mol × 1 L/0.100 mol × 1000 mL/1 L

= 100. mL

What are bacteria? Are they good or bad?

Answers

Answer:

Bacteria are a type of biological cell. They constitute a large domain of prokaryotic microorganisms

some are good some are bad

Explanation:

Other Questions
An author claims that "Athletes caught using performance-enhancing drugs should be sentenced to prison." The author provides the following reason as support:Last year, 709 citizens were caught using steroids. 403 were put in jail. In the same period of time, 120 professional athletes were caught using steroids. None of them was sent to prison. There is no reason why athletes should not be punished just like everyone else.Which choice best describes the reason the author provides? (5 points) aIt is effective. It supports the claim clearly and logically. bIt is emotional. It expresses personal feelings that cannot be backed with research. cIt is irrelevant. It discusses a fact that is off topic and does not support the claim. dIt is unverified. It does not cite a source to show where the information was located. Which of the following are phrases you would use with the preteritetense? (check all that apply) A letter to my mother telling her about my new english teacher Solve for the unknown 7/G = 35/50 100 Points Please HelpExplain the causes of the American Revolution as they impacted Georgia;include the French and Indian War, Proclamation of 1763, and the Stamp Act. A farmer sells 9.2 kilograms of pears and apples at the farmer's market. 3/4 of this weight is pears, and the rest is apples. How many kilograms of apples did she sell at the farmer's market? Express your answer in fraction and decimal form. Zachary invested $700 in an account paying an interest rate of 4.9% compounded continuously. Assuming no deposits or withdrawals are made, how long would it take, to the nearest year, for the value of the account to reach $1,360? What is the additive inverse of 6x +2? What would be the new value of a after running the program var a= 3 var b=5 a=a*boptions815375 Does Shakespeare make a point that you can or can not control another person? Why? Please support your response with relevant connections from the video Cite specific character experiences from the video that supports your answer Explain using at least 50 words, less than 50 words will result in a grade deduction Clearly explain why the characters want to control Include at least 3 ways your characters were successful or unsuccessful in controlling another character A regular heptagon has sides measuring 26 mm and is divided into 7 congruent triangles. Each triangle has a height of 27 mm. What is the area of the heptagon? max and min of f(x)=x^2+8x+14 what was the english bill of rights Which statement best describes Olmec religious beliefs?The Olmec worshipped multiple gods.The Olmec considered llamas to be sacred.The Olmec worshipped the god of nature.The Olmec considered head carvings to be sacred. An epithet is oftenA. negativeB. mournfulC. helpfulD. understated Classify the number 0 into as many categories as it belongs: Natural number, whole number, integer, or rational number. Jabari Manufacturing, a widgets manufacturing company, divides its production operations into three processesDepartment 1, Department 2, and Department 3. The company uses a process costing system. Jabari incurred the following costs during the year to produce 4800 units: Department 1 $17,000 Department 2 $7000 Department 3 $10,000 If Jabari could sell only 3100 units during the year, what will be the cost per unit of widget produced? (Round your answer to the nearest cent.) A) $10.97 B) $5.00 C) $7.08 D) $3.54 blank is the exponential form of 3 x 3 x 3 x 3 x 3 Chapter 5 Questions Answer the following items and upload your responses to the appropriate drop box by the due date. 1. Orange Sun Manufacturing, Inc. produces high quality sunglasses which are marketed and sold under various brand names. The production engineers have determined that each line employee accounts for approximately 10 units per labor hour. If employees work an average of 2000 hours per year, and projected sales for 2017 are 9.5 million units, how many line employees will we need for the coming year Can anyone help me???