Which systems help an organism maintain its structure and shape? A. skin and nervous systems

B. skeletal and muscular
systems

C. endocrine and digestive systems

D. muscular and excretor systems

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

The image shows a group of fish. the type of social behavior shown in the image is called

Which does not describe a physical change happening to water? water evaporating in the sun water reacting with nitrogen gas water freezing and being broken apart with a knife water heating up on a stove