Why do leaves have different sizes?

Question

this is home work and I would like to know why some plants have big leaves while others are small.

Answer 1

Each breed of plant has to adapt to local conditions.

A large leaf can soak up more sunlight and get more energy, but it's also more likely to be eaten. A larger leaf also provides a broad surface that can be affected by evaporation. A good example is an oak.

A smaller leaf may soak up less sunlight, but it's less likely to be eaten, and the plant will not be affected as much by evaporation out of the leaf. An example here would be pine trees and the various species cactus.

Answer 2

adaptation.