Question

stomata remain closed in a desert plants . how do they obtain carbon dioxide for photosynthesis

Answer 1

In desert plants the stomata open at night.

They take in CO2 at night, and is stored in the form of an intermediate which is used during the day for photosynthesis(when the stomata are closed).

Also, the chlorophyll of the plant are located in stem as leaves are reduced to spines and stem takes the function of photosynthesis.