How many chambers does the heart contain?
a. 3
b. 4
c. 5
d. 6

The best answer is b.  4

The human heart has  four chambers - two atria and two ventricles.

1. Right atrium -  receives oxygen-poor blood from the body and pumps it to the right ventricle.

2. Right ventricle -  pumps oxygen-poor blood to the heart.

3. Left atrium - receive oxygen - rich blood from the  lungs.

4. Left ventricle - pumps oxygen rich blood to the body.

The heart is a muscular organ. It is about the size of a closed fist. It is located in the thoracic cavity. It is protected by the rib cage and is the major organ of the circulatory system.

some fungi obtain their nutrients from a living host (plant or animal) and are called most biotrophic fungi have fairly narrow host ranges—they are specialized on a limited called rhizomorphs that allow the fungus to grow from one tree to another. ascospores are formed inside a sac-like structure called an ascus. so your answer is a

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.