Medical; a small parts in a cell that help your body to turn food into energy.

microscopic organism. Extremely small living thing that cannot be seen.

infective agent that is able to multiply only within the living cells of a host. Living organisms that causes disease or sickness.

chemical element of atomic number 7.

Thing you think about so much it's unhealthy.

member of large group of unicellular microorganisms.

arrangement of and relations between parts or elements of something complex. The ways some things are built, arranged or organized. construct or arrange according to plan.

living organism. Living creatures that are not plants or people.

Focusing on the bad aspects; pessimistic. no. Reply to a question or statement that means 'no'. refuse to accept.

organism consisting of cell or cells in which genetic material is DNA in form of chromosomes contained within distinct nucleus. Organisms with cells characteristic of all life forms except primitive microorganisms such as bacteria.

branch of science that deals with microorganisms.

class or division of people or things regarded as having particular shared characteristics.

To open an essay to set the scene.

as stated by. To give (someone) the respect due to them.

gladly received. used to greet someone in polite or friendly way. instance or manner of greeting someone. To greet someone who has just arrived.