3. The absorptive effectiveness of the small intestine is enhanced by increasing the surface area by
A villi.
C. digestive juices
B. enzymes.
D. elasticity of intestine,​

A villi.

Explanation:

Small intestines have finger-like extensions that basically increase the surface area for nutrients to attach and get transported inside the bloodstream or cells.

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).