Lactose intolerance is caused by:

A. inadequate exposure to dairy products
B. too much lactase in the diet
C. the lack of or reduction of the enzyme lactase
D. lack of hydrochloric acid in the gut lack of amylase

C

Explanation:

Lactose intolerance occurs when your small intestine doesn't produce enough of an enzyme (lactase) to digest milk sugar (lactose). ... If you're lactase deficient, lactose in your food moves into the colon instead of being processed and absorbed

regulation of gene expression. gene expression can be regulated by various cellular processes with the aim to control the amount and nature of the expressed genes. these regulatory proteins bind to dna and send signals that indirectly control the rate of gene expression

explanation:

it's anything that aren't producers and consumers.

explanation:

you've got to be clear on what "this" is