Help me pls ill give extra points

Ascientist and her team counted 200 individual deer in an area of 10 square kilometers. what is the population density?

Which statement best describes a keystone species? o a. it has littlelmenetic variation. it has an extremely high population. 0 b. 0 c. it remains unaffected by all environmental changes. od. it has a strong influence on the ecosystem. 0 e. it's the first species to populate a new ecosystem.

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist