The Thick, Green Stems and Spike-Like Leaves of Cacti and Euphorbias

The thick, green stems and spike-like leaves of cacti and euphorbias are adaptations to:

A) collect light in environments that have limited amounts of light.
B) conserve water in dry environments.
C) increase gas exchange in oxygen-poor environments.
D) speed up heating and cooling in environments that have little temperature fluctuation.
E) take up atmospheric nitrogen in nutrient-poor environments.