Answer:
D. By diffusion across a capillary wall
Explanation:
D is the best answer because gas exchange takes place in our lungs. Our lungs have alveoli which have a network of tiny blood vessels called capillaries, here the O2 diffuses the capillary wall to enter the bloodstream, and similarly CO2 diffuses out and we exhale it our from our lungs.
To be an animal trainer you should major in zoology
What do you mean by your question
I believe that the term metabolic rate reflects the energy the body needs to perform only its most essential activities. It is the rate of energy expenditure per unit time by endothermic animals while at rest, or the amount of energy that a person need to maintain the body functions while at rest per unit time.
The fundamental property of nervous tissues which related to its function of coordinating the body's activities is that it's widely connected to all areas of the body through the spine and neuronal axons in general. Nervous tissue which is found in our brain can exert its "will" and affect all parts of our body.
