The cell wall of which of these is not made up of cellulose?

State whether the following statement is true or false:
$RER$ looks smooth under a microscope because it has particles called ribosomes attached to its surface.

Why are plastids called the 'kitchens of the cell'?

$(a)$ Which major invention led to the discovery of the microscopic world?
$(b)$ Name a single cell which may constitute a whole organism. What are they called?
$(c)$ Every multicellular organism has come from a single cell. Justify the statement.

Name the cell organelles which are without a membrane.

Which of the following are covered by a single membrane?