The sickle-cell allele for hemoglobin, which affects both red blood cell shape and resistance to malaria, provides an example of (a) codominance. (b) pleiotropy. (c) incomplete dominance. (d) a...

The sickle-cell allele for hemoglobin, which affects both red blood cell shape and resistance to malaria, provides an example of

(a) codominance.

(b) pleiotropy.

(c) incomplete dominance.

(d) a polygenic trait.

Crossing over occurs during which phase of meiosis?

(a) metaphase I

(b) prophase I

c) anaphase II

(d) prophase II