Answer:
It's important for a scientist to try to hold all variables constant except for the independent variable. If a control variable changes during an experiment, it may invalidate the correlation between the dependent and independent variable. When possible, control variables should be identified, measured, and recorded.
The correct answer is hydrocephalus.
Hydrocephalus refers to the condition in which the accumulation of fluid takes place in the ventricles (cavities) deep inside the brain. The excess fluid enhances the size of the ventricles and applies pressure on the brain. The cerebrospinal fluid usually flows via the ventricles and bathes the spinal column and the brain.
Because plants go through a cycle(the cycle is seed, seedling, plant, flower and tree.) and it takes time for the plant food, water, and nutrients to go though the plant.
Accumulation of substances such as pesticides or other chemicals in an organism
