A control is a experimental variable that is kept constant or unchanged during an experiment. During a controlled experiment, the controlled variables are held constant to minimize or stabilize their effects on the subject, its unchanging state allows the relationship between the other variables being tested to be better understood.
I think the answer is naturally acquired active immunity..also depends on which disease
Answer:
- CO2
- H2O
Explanation:
Candle is made up of paraffin wax which is a type of hydrocarbon like methane. When the hydrocarbon comes into contact with oxygen. Carbon dioxide and water are produced. the light produced is due to the combustion of the hydrocarbon.
Answer:
D
Explanation:
The hertz (symbol: Hz) is the derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second.
The population of their prey most likely increased causing an imbalance in the food chain. This is true since there probably was not enough food to feed the rapidly increasing population.