Final answer:
The soft substance inside a coconut is called the endosperm, which provides nutrition to the developing seed. The coconut's pericarp includes the exocarp, mesocarp, and endosarp, analogous to the protective shell of a peanut and the hull of a corn kernel.
Step-by-step explanation:
The inside of a coconut is often referred to as the endosperm, which is a soft substance of a fruit that develops from the polar nuclei after fertilization.
This endosperm can be considered a source of nutrition for the developing seed. In the case of a coconut, the endosperm is initially in a liquid form known as coconut water, and as the coconut matures, it solidifies to form the white, fleshy coconut meat.
The pericarp is the collective term for the structure that encloses the seed, including the exocarp, mesocarp, and endocarp.
To give more context, a peanut has a shell which protects the seed, and corn kernels have a hull, which is a thin part that sometimes gets stuck in your teeth.
Similarly, in a coconut, the pericarp surrounds the endosperm which nourishes the developing plumule, or young shoot, from the germinating seed.