What is the movement of molecules from an area of lower concentration to one of higher concentration, with carrier molecules using energy called?
a.
osmosis
b.
mitosis
c.
diffusion
d.
active transport

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.

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?

Why has two different alleles for the same trait?