A cow is given a growth hormone and then compared to another cow that was not given a growth hormone. Both cows were weighed at 2 years.

The complete question is as follows:

A cow is given a growth hormone  and then compared to another cow that  was not given a growth hormone. Both  cows were weighed at 2 years. What is the independent variable?

if the cow is given growth hormone or not  

weight of the cow

same cows  

type of growth hormone

The correct answer is - if the cow is given growth hormone or no

Explanation:

The independent variable is here is if the growth hormone is given or not as the variable which is subject to change or manipulated during an investigation and affects the dependent variable is known as the independent variable.

Due to this independent variable manipulation the weight of the cows might be different which makes the weights as the dependent variable.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.