AP BIOLOGY

Detailed explanation-1: -The most common methods are wind, water, animals, explosion and fire. Dandelion seeds float away in the wind.

Detailed explanation-2: -In woolly fruits and seeds, the pericarp or the seed coat is covered with cottonlike hairs-e.g., willow, poplar or cottonwood, cotton, and balsa. In some cases, the hairs may serve double duty in that they function in water dispersal as well as in wind dispersal.

Detailed explanation-3: -Animals disperse seeds in several ways. First, some plants, like the burr at left, have barbs or other structures that get tangled in animal fur or feathers, and are then carried to new sites. Other plants produce their seeds inside fleshy fruits that then get eaten be an animal.

Detailed explanation-4: -Conclusion: Dispersal of seeds is important for the survival of species in new places and also helps to avoid overcrowding and competition for food and resources.

Detailed explanation-5: -The seed coat has two layers, the outer testa and the inner tegmen. Hilum: The hilum is a scar on the seed coat through which the developing seed was attached to the fruit.