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 overall health. Factors such as climate, environment, and genetics play a significant role in determining leaf shape. For example, leaves in hot, dry areas may be smaller and more needle-like to reduce water loss, while those in humid environments may be broader to maximize sunlight absorption.