An individual who is heterozygous for a gene has:
a. alleles at a given locus that are different from one another
b. alleles at a given locus that are the same.
c. alleles at different loci that are the same.
d. a recessive gene on chromosomal pairs.

A.

Explanation:

When we say that an individual is heterozygous, it means that the two alleles at the locus we are studying are different from one another. That is, each one of the parents contributed a different allele.

On the other hand, If the alleles at that locus were the same we would say the individual is homozygous. In other words, the two parents contributed each the same type of allele.

is in the form atp or adenosine triphosphate

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.