<span>Yes, all living organisms are made of at least one cell (cell theory). But, remember, viruses and prions, which cause diseases, are not technically living things, and they are NOT made of cells. Also, if asked a question similar to this on a biology test, the teacher may be trying for an answer similar to: "Organisms are made of different organ systems, which are made of various related organs, which are made of different tissues working together, which are made of cells". </span>
This is correct your Retna is in the back of you eye
The answer is B. Oxygen
To do aerobic respiration, oxygen is needed. Without oxygen, the body won't produce some substance which will be needed to do Krebs cycle and electron transport. Most of the energy will be produced by the electron transport so without oxygen the amount of energy produced will be much less.
Planting trees would help......................................................