Well a person breathes harder when he/she exercizing because you are working hard and your body is not used to it so your trying to pass more air through the lungs
This question doesn't make since. it could mean its death rate is lower than its birth rate or it could mean just expansion
A.) Burning waste is bad because it will pollute the atmosphere. So this is not the answer.
B.) More coal based electricity will mean more smoke and ground pollution. Not the answer
--> C.) Starting recycling programs will help reuse the material rather than tossing It in a landfill. This is the correct answer.
D.) Driving cars means pollution, again, it releases carbon monoxide into the air which is bad for the ozone layer of the earth.
It is very important to control the conditions of an experiment because FAILURE TO DO THIS WILL MAKE THE RESULTS OF THE EXPERIMENT INVALID.
A controlled experiment refers to an experiment that is conducted under controlled conditions. Conducting experiments under controlled conditions helps scientists to minimize the changes in all other variables with the exception of the ones been tested.