Chemistry as a subject has a significant importance in our daily lives and the society in general. Everything on the earth is made of chemicals. ... It also describes various chemical elements preset in the environment, their reactions, and effects on the environment.
Answer: A
Explanation: gravitation keeps moon in circular orbit.
Without gravitational force Moon would move in
Linear path.
Answer:
many alveoli are present in the lungs with a shape that further increases surface area. Thin walls - alveolar walls are one cell thick providing gases with a short diffusion distance. Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface.
Explanation: