What is an allele?
o
a. an organism that lives in eukaryotes
o
b. a group of chromosomes
o
c. a gene that causes a specific trait
o
d. a chromosome that determines gender

Just did the lesson on this, the answer is  C.

Explanation:An allele is one of the possible forms of a gene. Most genes have two alleles, a dominant allele and a recessive allele. If an organism is heterozygous for that trait, or possesses one of each allele, then the dominant trait is expressed. ... So a gene is a particular region of your DNA that controls a specific trait.