Which of the following are covered by a single membrane?

Why is the mitochondrion called the 'powerhouse of the cell'?

Cell secretions are done by

Name the scientist who discovered cells. List any two single-celled (unicellular) organisms.

When observed under a microscope,small pores are seen in the epidermis of the leaf. What are these pores called? Write two functions of these pores.

We eat food composed of all the nutrients like carbohydrates,proteins,fats,vitamins,minerals,and water. After digestion,these are absorbed in the form of glucose,amino acids,fatty acids,glycerol,etc. What mechanisms are involved in the absorption of digested food and water?