Cam plants have adapted to arid environments by closing their stomata during the day. however, photosynthesis still occurs. this is because view available hint(s)
a) co2 is fixed in the bundle-sheath cells some
b) co2 leaks through the closed stomata
c) co2 is fixed at night when the stomata are open photosynthesis occurs at night

C) CO2 is fixed at night when the stomata are open photosynthesis occurs at night

Explanation:

CAM plants exhibit temporal separation of CO2 uptake and CO2 fixation to reduce the water loss. Air is moist and cooler at night. These plants open the stomata at night to allow the CO2 to enter the leaf cells. The entered CO2 is fixed into oxaloacetate which in turn is reduced into malate and is stored in vacuoles. Stomata remain closed during day time to prevent water loss. Decarboxylation of malate releases CO2 which in turn enters the C3 cycle to form glucose.