Leaf shape refers to the physical form and outline of a leaf, which can vary widely among different plant species. Common shapes include oval, lanceolate, heart-shaped, and palmate. The shape of a leaf can influence its ability to capture sunlight and perform photosynthesis, as well as its water retention and resistance to environmental stress. Factors such as climate, soil type, and evolutionary adaptations play a significant role in determining leaf shape. For example, plants in arid regions may have narrower leaves to reduce water loss, while those in humid environments may have broader leaves to maximize light absorption.