What are the similarities
and differences between experiments and obser-
vational studies?

experiment, the researcher will undertake some experiment and not just make observations

while the observational study, the researcher simply makes an observation and arrives at a conclusion.

additional tip/info: The observational studies are cheaper than experimental ones and can take as much time as needed.

i believe you meant to say air rather than hair so the answer is below ")

the dead sea, the lowest place on earth at 430 metres (1,410 ft) below sea level, has a correspondingly high typical atmospheric pressure of 1065 hpa.

digestion

it excretes wastes