Answer:
A decrease in biodiversity causes a decrease in ecosystem stability, because a change to one organism will have a greater impact on the entire ecosystem. With greater biodiversity, the loss of one type of organism could be moderated by the adaptation of other organisms to fill its role.
Aerobic exercise is the body producing energy WITH the use of oxygen (light activities like jogging). Anaerobic exercise produce energy without the use of oxygen and is typically a higher intensity that burns fat AND helps gain lean muscle mass (these are activities like weight lifting).
"severe weather conditions" are the only things than can be reasonably well predicted with the help of science. Of course the accuracy of these predictions varies greatly.
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