Which structure gives strength and rigidity to a plant cell? a. nucleus b. chloroplast c. mitochondrion d. cell wall

This is the diveristy of ecosystems natural communites and habits it is the variety of ways that species interact with each other and their environment

When is your breathing likely to speed up? a. when your white blood cells increase b. when your cells need more energy c. when your heart cells need more carbon dioxide d. when your blood cells have too much oxygen

The offspring of two different species