He was the first to provide an explanation of evolution supported by evidence.
D. In a regimen of two to four drugs
That would be living things.
Because...
Biosphere= living things
Lithosphere= land
Hydrosphere= water
Atmosphere= air
Answers
When doing medical research with human subjects, the following are unavoidable limitations;
It’s often impossible to repeat trials on the same subjects.
Subjects may report an inaccurate medical history.
It can be difficult to control all possible variables
There are ethical or privacy concerns to consider.
Explanation
When doing a medical research that involves human subjects it should be voluntary, informed and consent. The researchers should respect the persons treated as autonomous agents. The volunteers should be protected from physical, mental and emotional harm. The benefits should outweigh the costs.
