How are a tundra and a desert different? A tundra has a lot of precipitation and a desert has little.
A tundra has few trees and plants and deserts have many.
A tundra has soil that is often sandy and a desert has grass.
A tundra is dry and cold and a desert is dry and hot.

a. to encourage apoptosis

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.