2.     when an animal receives a vaccine, about how long will it take before the animal's immune system will protect the animal from disease?           a. two days    b. two hours    c. two months    d. two weeks

The answer is option A.

Explanation:

The resistant framework attempts to keep germs out of the body and wreck any that get in. The safe framework is comprised of an unpredictable system of cells and organs that shield the body from contamination. Lymph hubs are a piece of the safe framework. They discharge lymphocytes, a specific sort of white platelet that battles infection.The safe framework ensures the body against sickness or other conceivably harming remote bodies. When working legitimately, the insusceptible framework recognizes and assaults an assortment of dangers, including infections, microscopic organisms and parasites, while recognizing them from the body's very own sound tissue.

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.