How come plant cells have a cell wall but our cells don't?

How is the national wildlife refuge system similar to the pacific region coastal program? a. both programs are concerned with providing habitats for wildlife b. both programs are primarily concerned with preserving fish species c. both programs have set aside 150 million acres of land d. both programs are under the u. s. fish and wildlife service

What substance acts to prevent sudden ph changes in bodily fluids?

Which feature would you expect to find in a population in which sexual selection depends on male competition?