Why are regular visits to the doctor important for maintaining your optimal immune health?
a) to be sure that your overall health is good and to receive the necessary vaccinations
b) to identify any problems with your immune system early and to increase the stress you are under
c) to avoid making contact with sick people and evaluate your weight
d) to check on the status of your growth and maintain your weight

A) to be sure that your overall health is good and to receive the necessary vaccinations

Explanation:

I can confirm the correct answer is A. I Just did the quiz.

Explanation:

the reason the two sea urchins don't compete with each other for food, resources, etc. is because the urchins have adapted to the environment but they have also adapted to each other. this is most likely because the genes of the sea urchins.

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)