Rickettsia is an example of an which can only replicate inside a host cell.

a » opportunistic infection

b » obligate intracellular parasite

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

Plants that have reproductive structures called cones are?

Describe how alleles and genes are related