How do lysosomes perform the functions of defence,digestion and cleansing in the cell?

Do you agree that '$A$ cell is a building unit of an organism'? If yes,explain why.

$(a)$ 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.

Who discovered the Golgi apparatus? Describe its structure and functions.

Give the chemical composition and functions of plasma membrane and cell wall. Differentiate between the two.

Which type of animal cell lacks both mitochondria and endoplasmic reticulum?