4. Which statement is an example of how environmental factors affect gene expression?
A. Your finger becomes callus from writing with a
pencil
B. The amounts of sun, water, and nutrients affect the
growth of a plant
C. Parents with red hair have a child with red hair
D. A red snapdragon flower is crossed with a white
snapdragon flower to produce a pink snapdragon flower.

B. The amounts of sun, water, and

nutrients affect the growth of a plant

Explanation:

Gene expression is the way by which the genes of an organism instructs the production of proteins, which are responsible for the organism's phenotype. However, the trait or characteristics possessed by organisms are not strictly or 100% dependent on the genotypic factors but also on the environmental factors.

Environmental factors are the biotic (living) and abiotic (non-living) factors that affect organisms development and growth. An example is how the amount of sun, water, and nutrients, which are all environmental factors, affect the growth of a plant. Growth in plant, therefore, affects gene expression.

not sure if this what   you'r looking for would be percent composition

a. suckling by young

b. hypothalamus

c. dopamine

d. trh

e. anterior pituitary

f. mammary glands

g. milk production