Why was the concern over global cooling replaced with a concern over global warming?
a.
the science community needed a cause to frighten the general population.
b.
steady surface temperature increases were noted between the 1970’s and 90’s.
c.
air pollution only became a concern in the 1980’s.
d.
scientists observed severe ocean acidification.

lunar landing mission. apollo 11 was the first manned mission to land on the moon. the first steps by humans on another planetary body were taken by neil armstrong and buzz aldrin on july 20, 1969. the astronauts also returned to earth the first samples from another planetary body.

explanation:

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

a and c are the answeres

hello

answer: collecting information/data

reason: the student is going around and asking people questions to collect data

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