Explanation : Statement I : This is correct. The olfactory receptors are specialized cells in the nasal cavity that are responsible for the sense of smell. They are coated with mucus which helps to dissolve odor molecules, making them easier to detect. Statement II : This statement is incorrect due to a mix-up in the description of the layers. The wall of the eyeball indeed has three layers but they are as follows: 1. The external layer is the sclera, which is a dense, tough white connective tissue that gives the eye its shape and protects the inner components. 2. The middle layer is the choroid, which is a thin pigmented layer that provides oxygen and nourishment to the outer layers of the retina. 3. The internal layer is the retina, which contains photoreceptor cells (rods and cones), bipolar cells, and ganglion cells, and is responsible for detecting light and transmitting these signals to the brain through the optic nerve.
