Answer:
The answer is C) osteopenic
A+,A-,O+ and O- can give to blood type A+
I think the correct answer would be strong gravity. The factor that allows the earth to hold onto water would be the strong gravitational pull of the earth. In fact, it is what holds everything onto earth not only water. Hope this answers the question.
so that it follows the law of conservation of mass.
have a goed day