What human body system sends signals to glands in the endocrine system to release hormones?
a. circulatory system
b. excretory system
c. nervous system
d. digestive system

Which statement best describes the relationship between an allele and a gene? question 1 a. an allele is a variation of a gene that can be expressed as a phenotype. b. an allele is the part of a gene that attaches to messenger rna molecules. c. an allele is a segment of a dna molecule that controls replication of a gene.

When the oxygen produced by photosynthetic plants in the water dissolves in the water, which of these is being formed?

Describe the relationship between isotonic solutions, equilibrium, and water movement into and out of a cell.