Why is it important to understand the nutritional content of food

What links the two strands in a dna helix together in the middle? a. phosphate groups b. sugar rings bonded together c. proteins d. bases with hydrogen bonds

How is the male reproductive system different from other body systems? it isn’t necessary to vital signs. it monitors other body systems, and adjusts if necessary. it transports items from one system to another. it is the only system that produces hormones in the male.

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.