In unicellular organisms, are all life sustaining processes performed by single cell?

Despite lacking a centralizing organ, such amoebae are capable of regulating their nutrient supply. When faced with diverse nutritional situations, they adapt so as always to select an optimal ratio of nutrients.

Explanation:

Asyou know, some organisms are multicellular, which means theyare made of many cells. For example, birds and trees are multicellularorganisms. You are also a multicellular organism. Other organisms,including some pathogens, are single cells. The name given to single-celled and other very small organisms is Usually, amicroscope is necessary to observe microorganisms. You can thinkabout the wide variety of living things as belonging to one of twogroups. One group contains mostly microscopic organisms, while theother contains organisms you can see without a microscope

the answer is:

carbon dioxide