Lactase is an enzyme that is produced in the lining of the intestines. this enzyme the body speed up the breakdown of carbohydrates that are found in dairy products, such as milk, yogurt, and cheese. which general function does lactase perform? fighting disease creating movement regulating cell processes sending chemical messages

The general function that lactase does (as given in the choices you provided above) would be regulating cell processes. Lactase is one of the proteins in the body that help metabolize or break down lactose into simple sugars in order for it to be digested properly. If lactase is not produced, you become lactose intolerant. 

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.

idk why hjggjhjkhj