Answer:
In this research, environmental stimulation would be considered the independent variable.
Explanation:
In research, the independent variable is the characteristic that tends to be controlled or modifyed to study its effect on another variable (that is known as the dependent variable). In the case presented, the researcher wants to study the effect of environmental stimulation on the prain development; the dependent variable is the brain development of young infants and the independent variable is the environmental stimulation, that is believed to have an effect on the brain development (dependent variable).
If he were to conduct an experiment, he would control or change the environmental stimulation (independent variable) in order to observe the changes in the brain development (dependent variable).
If he used a repeated -measures design then there would be 30 subjects in the research studies.
4. Harsh climate conditions
The first one is C and the second one is A
I think...
I think you should wait for another answer just in case
But i hope this helps u