There are often not more than one or two independent variables tested in an experiment, otherwise it is difficult to determine the influence of each upon the final results. There may be several dependent variables, because manipulating the independent variable can influence many different things.
Answer:
Variola virus.
Explanation:
Smallpox is caused by a virus named as Variola virus.
Answer:
In primary succession there is no presence of soil or the soil cannot support life in secondary succession there is a presence of soil in which it can support life
Explanation:
Answer:
water is an abiotic factor
