The undefined nuclear region of prokaryotes is also known as:

Explain how cell walls permit the cells of fungi to withstand very dilute external media without bursting.

$(a)$ What are the consequences of the following conditions?
$(i)$ $A$ cell having higher water concentration than the surrounding medium.
$(ii)$ $A$ cell having lower water concentration than the surrounding medium.
$(iii)$ $A$ cell having equal water concentration to its surrounding medium.
$(b)$ Name the materials of which the cell membrane and cell wall are composed.

$(a)$ List any two structural differences and two similarities between a plant cell and an animal cell.
$(b)$ What would happen if an animal cell is kept in distilled water for $24$ hours?

Define the following terms:
$(i)$ Endocytosis
$(ii)$ Phagocytosis
$(iii)$ Exocytosis

Name the longest cell of the human body.