The correct answer is b. They minimize water loss.
Desert plants such as Acacia, Opuntia are adapted to live in the arid environment. They are adapted in many ways, on such is they have either small leaves or leaves are modified into spines. These adaptation are to conserve water. Small leaves have very small surface area which help to reduce water vapor loss during transpiration. Besides, a small leaf doesn’t reach as high a temperature as a large leaf in the sunlight.
