Can someone help me out with these 2 biology multiple choice questions?

Vaccines provide immunity to diseases for some period of time (usually years) because: A. They introduce antibodies that stimulate antigen production and effective B-cells are produced that stay in your body for years and provide immunity B. They stimulate the innate immune system to produce antibodies C. They... show more Vaccines provide immunity to diseases for some period of
time (usually years) because:
A. They introduce antibodies that stimulate antigen
production and effective B-cells are produced that stay in
your body for years and provide immunity
B. They stimulate the innate immune system to produce
antibodies
C. They stimulate the production of more B and T cells which
in turn lead to long term immunity
D. Vaccines introduce an antigen that ultimately causes the
production of antibodies by B cells that stay in your body
for years
E. Vaccines contain the DNA of viruses that get into your
cells and stimulate the production of antibodies that fight
off infections

In a single population of water snakes on an island
in Lake Erie, some snakes have 19 black bands on
their back, some have none but most have between
5-10 bands. Originally, how did this color variation
arise in the population?

A. Through natural selection
B. The bands help snakes survive better on rocks
C. Through random mutations
D. There is no way to know
1 answer 1