AP BIOLOGY

Detailed explanation-1: -Animals can disperse seeds by excreting or burying them; other fruits have structures, such as hooks, that attach themselves to animals’ fur.

Detailed explanation-2: -Plants such as burdock have hooks to which the seed is attached. These hooks easily get caught in the fur of mammals as they pass by the plant. At some point the seed will fall, often a considerable distance from the parent. If conditions are right the seed will germinate and grow into a new plant.

Detailed explanation-3: -Xanthium seeds are produced inside a hard, spiny, double-chambered, single-seeded bur which is 0.8 to 2.01 cm long. As the seed is covered with stiff spines that are hooked, they stick to the fur of animals.

Detailed explanation-4: –Seeds with hooks attach to the fur of animals or clothes of humans and are dispersed to a sufficient distance. They might then fall off and germinate into a new plant under suitable conditions. So the correct answer is option C) Animals.

Detailed explanation-5: -Many plants produce fruits or individual seeds covered in hooks or spines which attach the seed to the animals’s fur or feathers-or, in the case of humans, to our clothes or bags. The seeds are then carried a sufficient distance from the parent plant to give them space to grow.