AP BIOLOGY

Detailed explanation-1: -The seed coat has two layers. The outer layer is thick and known as the testa. The inner layer is thin and known as tegmen.

Detailed explanation-2: -The protective covering of seed is called seed coat and is made up of two layers. Outer layer which is usually hard is called testa and the inner layer which is thin and papery is called tegmen.

Detailed explanation-3: -A hard seed coat protects the seed not only from mechanical stress but also from microorganism invasion and from temperature and humidity fluctuations during storage. Phenolic compounds in the seed coat contribute to seed hardness and inhibition of microorganism growth.

Detailed explanation-4: -After fertilisation, the ovary develops into fruit and the ovule develops into a seed. The outer seed coat is called the testa and the inner coat is called the tegmen.

Detailed explanation-5: -Some seed coats are hard like corn and sunflower seeds. Other seeds have soft seed coats like marigolds, tomatoes, zinnias, peppers, and cucumbers. All seeds need the right combination of water, oxygen, and the right temperature for the seed to grow.