The structure B in the seed can be identified as testa (option c) rather than plumule or radicle.
What is the testa in a seed?
The testa is the outer seed coat that protects the seed. It is the outermost layer of a seed, providing a protective covering for the embryo (the developing plant inside the seed) and the endosperm (a tissue that provides nutrients to the embryo).
Some of the functions of this layer are:
- Protection of inner structures in the seed.
- Water uptake regulation.
- Gas exchange.
- Facilitate seed dispersion.