Biosphere II is a self-contained ecological system that was sealed with researchers inside. Unfortunately, the microbes in the soil consumed rich organic matter and produced carbon dioxide. Oxygen levels plummeted and, subsequently, the mission failed. This depletion of oxygen was caused by small microorganisms carrying out the process of

cellular respiration

Explanation:

Cellular respiration is the metabolic reactions and processes of a cell, which involve the conversation of biochemical energy in food molecules into energy in the form of ATP and also release waste products. The cells of these small microorganisms that carry out cellular respiration as they consume rich organic matter, use up a lot of oxygen as they produce a lot of carbondioxide in this process as waste.

humans are now responsible for causing changes in the environment that hurt animals and plant species. we take up more space on earth for our homes and cities. we pollute habitats. human activity often changes or destroys the habitats that plants and animals need to survive.