D. A set of steps that help scientists gather knowledge
http://www.atnf.csiro.au/outreach/education/senior/cosmicengine/stars_hrdiagram.html. This will give u the answer, just go to link
Answer: because it consists of more than one element, which are hydrogen and oxygen in a covalent bond.
Answer: Option (A) is the correct answer.
Explanation:
Force acting on a dam is as follows.
F =
.......... (1)
Now, when we double the depth then it means H is increasing 2 times and then the above relation will be as follows.
F' = 
F' =
........... (2)
Now, dividing equation (1) by equation (2) as follows.
=
Cancelling the common terms we get the following.
=
4F = F'
Thus, we can conclude that if doubled the depth of the dam the hydrostatic force will be 4F.