It is important because we need to learn the environment, what is around us.
The third one,
Autotrophs use a process called photosynthesis to make their food. In photosynthesis, autotrophs use energy from the sun to convert water from the soil and carbon dioxide from the air into a nutrient called glucose. Glucose is a type of sugar. The glucose gives plants energy. Plants also use glucose to make cellulose, a substance they use to grow and build cell walls.
The answer to your question is A.
Providing long-term control over the body's internal conditions
Keeping conditions within a normal range
Adjusting the "set point" for body temperature based upon level of activity
Zero degrees latitude is the line designating the Equator and divides the Earth into two equal hemispheres (north and south).