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.
I temperature will continually rise until it melts assuming you do not stop applying heat to the ice. It doesn’t really matter at what temp below freezing you start as long as you go above freezing the ice will melt.
That depends on what you mean by ripples at the beginning of time. If you are referring to inflation of the universe caused by the Big Bang, and the subsequent "ripples", then those ripples are the leftover, background radiation from the event. If you are referring to ripples in space-time, then it still could have multiple meanings.
Answer:
These neurons are located in the central nervous system (the brain and spinal cord). Afferent and efferent neurons have to work together in order to sense and respond to stimulus, but they don't directly connect. Association neurons bridge the gap to relay information between sensory and motor neurons.
Answer:
Fn = Shelf
Explanation:
The shelf is pushing the book upwards.