Answer:
circulatory
Explanation:
Heart is only responsible for generating the pumping force needed to supply blood to each and every corner of the body. As heart is part of circulatory system. The answer is Circulatory system.
Answer:
the troposphere directs the light towards us.
Answer:
The answer is synthesis :)
My guess:
I do not know the options to the blanks, but I'd say that the answer to the first one is "strongly linked". Think of a chromosome as a phylogenic chart → 2 species that are beside each other are strongly linked, if compared to 2 species 3 spots apart form each other. So, 2 genes that are close to each other are strongly linked.
I do not know the options to the blanks, but I'd say the answer to the second one is epistasis → which is the interaction between two different genes (different means they're not linked alleles).
Hope it helped,
BioTeacher101