Answer:
Immune
Explanation:
The immune system helps to protect our body from all sort of organisms ranging from invading toxins and micro-organisms which negatively affects an individual’s health and well being.
Stress has an adverse effect on the immune system such that it weakens and suppresses the functions of the required antibodies in the body system. This is the reason why many aged people fall sick because they have gone through more stress when compared to younger people.
On top of each kidney lies Adrenal gland. It's part of endocrine system. It's responsible for producing hormones like adrenalin, also steroids like aldosterone and cortisol. So in this case answer to your question is Adrenal gldans lie on top of kidneys
According to the research, the correct option is A, population genetics is the study of how allele frequencies in a population change over time.
<h3>What is population genetics?</h3>
It studies the origin, amount and distribution of genetic variability present in populations.
It explains the variation between individuals, as well as the dynamics of alleles and genotypes within and between populations.
Therefore, we can conclude that according to the research, the correct option is A, population genetics is the study of how allele frequencies in a population change over time.
Learn more about population genetics here: brainly.com/question/13049509
#SPJ1
