Question

green plants cannot live without light because ______.

a. they need light to breathe

b. light helps to warm them to the optimum temperature for growth

c. it is necessary for the manufacture of food

d. none of the above

Explanation:

Green plants perform photosynthesis to manufacture food (glucose), and light energy is essential for this process (photosynthesis equation: \(6CO_2 + 6H_2O \xrightarrow[\text{Chlorophyll}]{\text{Light Energy}} C_6H_{12}O_6 + 6O_2\)). Option a is incorrect as breathing (respiration) doesn't require light. Option b is incorrect as light's role in photosynthesis is energy for food production, not just warming. So option c is correct as light is necessary for food manufacture (photosynthesis).

Answer:

c. It is necessary for the manufacture of food