Name the cell organelle which you would associate with the elimination of old and worn-out cells.

$(i)$ Why is the cell called the structural and functional unit of life?
$(ii)$ Why is the plasma membrane called a selectively permeable membrane?
$(iii)$ Name the factor which decides the movement of water across the plasma membrane.

Name the following:
$(i)$ The cells which have a changing shape.
$(ii)$ The cells which have a typical shape.

What are chromosomes made of?

State whether the following statement is true or false:
Plastids are present in both plant and animal cells.

The undefined nuclear region of prokaryotes is also known as: