Causation can be proved by using a(n):
a
negative correlation.
o
b. experiment.
o
c. observatior..
d. hidden variable.
answer : !

I would say B

Explanation:

To prove Causation you need a random experiment. This could mean D because random experiments entail hidden variables but I think your best bet is B because its what's the use of a hidden variable without an experiment.

sexual reproduction produces offspring with novel combinations of genes. species that reproduce sexually must maintain two different types of individuals, males and females, which can limit the ability to colonize new habitats as both sexes must be present.

it would affect precipitation by causing flooding in some areas of the world due to climate increasing, causing the glaciers in the northern and southern pole of our planet to melt.

i wish you would have provided choices to simplify it and allow me to give an exact answer.