How does the nervous system help the body maintain homeostasis?
O A. It causes reflex actions when sudden action is needed.
O B. It balances the autonomic and somatic systems.
O C. It uses neurons to block the effect of hormones.
O D. It sends messages that control all the systems in the body.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.