Two points each. Ehleringer, et al. Cactus stems possess areoles. When a particular environmental factor is at its optimum, its relative effect upon cactus growth is assigned a value of 1.0. When a particular environmental factor is at its optimum, its relative effect upon cactus growth is assigned a value of 1.0.
Environmental factors act in combination to determine overall cactus growth.
In contrast, the majority of the stem cross section is yellow or yellow-white in color. Four points each. Answer questions with a brief discussion. A single sentence is too brief. Construct complete sentences.