Four general conditions necessary for natural selection to occur<span> are: A. More organisms are born than can survive. B. Organisms vary in their characteristics, even within a species. D. Differences in reproduction and survival are due to variation among organisms.</span>
Answer:
Respiratory and circulatory
Explanation:
The Circulatory System Works in Tandem with the Respiratory System. The circulatory and respiratory systems work together to sustain the body with oxygen and to remove carbon dioxide. Pulmonary circulation facilitates the process of external respiration: Deoxygenated blood flows into the lungs.
Always go with the second greatest. it has more of a consistent vibe so personaly id go with C
In the experiment, the independent variable is the drug amount. Experiment group is given certain amount of drug, control group is not given the drug. The dependent variable is the body fat. I think you means the control is the living environment including food and water.
The first scientist that said that planets travel in fixed paths or orbits is Kepler. A
