Question

Cam plants belong to _____ family.
A. Malvaceae
B. Crassulaceae
C. Trapaceae
D. Orchidaceae.

Answer 1

These CAM plants belong to family which are a diverse family of dicotyledonous flowering plants characterized by succulent leaves and a unique form of photosynthesis. Flowers generally have five floral parts.

Complete answer:
To answer this question, first, we need to know about CAM. CAM is short for “Crassulacean Acid Metabolism”, which is a method of carbon fixation evolved by some plants in dry circumstances. In most plants, the stomata – which are like tiny mouths that take in oxygen all along the surfaces of their leaves unblock during the day to take in $CO_2$ and release $O_2$.
Now, let us find the solution from the option.
CAM sorts for crassulacean acid metabolism due to the fact that it was first found in members of the plant family Crassulaceae (Bryophyllum). CAM is the fixation of carbon dioxide by plants in arid condition. In normal conditions, the opening of the stomata is always connected with the large losses of water.
To inhibit this loss during intense sunlight, CAM plants have developed a mechanism which allows the uptake of carbon dioxide during the night. They are more usual than C4​plants and consist of cacti and a wide variety of other succulent plants.

Thus, the correct option is B. i.e. Crassulaceae.

Note: Most plants unblock their stomata during the day because that is when energy is received from the Sun. The energy from the Sun is captured by the chloroplasts and utilized to produce ATP and NADPH. This short period energy storing molecules are then utilized to energize the fixation of carbon into sugar.