The answers that apply are;
new allele combinations were advantageous in the presence of
parasites with high mutation and reproduction rates.
sexual reproduction increased genetic variability and
survival in a changing environment?
Sexual reproduction increases genetic variability due to combinations of alleles from the parents to the
offsprings. This increases the chances
that a particular combination may be able to confer resistance to the
disease-causing bacteria and hence increase the survival of the roundworms population.
Answer:
What are the word options?
Explanation:
I believe this is a bit of a trick question, while you are right about both B and D, they both preexist they just develop into other structures. I believe the correct answer is A since the nerve cord is hollow not solid.
Homocystine is the amino acid.
Explanation:
Homocystine is an amino acid. Its a non proteogenous amino acid which is basically cystine by structure with an added sulphur bridge. In body, it's obtained from diet, as well as produced from methionine by decarboxylation.
This amino acid do have an important effect on blood vessels. It gets deposited on the inner surface of blood vessels in small dot manners which make the inner surface of blood vessels rough and irregular. This in turn increases the chances of intra Venous blood clot which can result in heart failure, AMI, brain stroke, kidney failure as well as Pulmonary embolism. Thus reduction of levels of homocystine is very necessary.