Which factor allows earth to hold onto liquid water?
a. strong gravity
b. weak salinity
c. freezing temperatures
d. presence of living things?

The answer is a. strong gravity.

Gravity or gravitational force is the downward force or pull exerted by the Earth on the matter present on its surface. The gravitational force of the Earth holds onto all the matter that is present within its sphere of influence or the gravitational field. The liquid water on Earth is present within its gravitational field, hence is held strongly in place on the surface of the Earth.

answer; i believe the correct answer is (replication is not conservative);

answer: a) a compound microscope has a greater magnification ability than a simple microscope.

explanation: