Ethical guidelines require researchers to weigh the potential benefits of research against possible
a.
biases in the research design.
b.
independent variables in the study.
c.
damage to laboratory equipment.
d.
risks to study subjects.

D

Explanation:

Humans are considered to have intrinsic dignity that can't be violated and is even protected by laws of human rights. Therefore, even when conducting experiments that will involve human subjected, it is expected by ethical standards of research are considered before being implemented. For example it is important that the experiment does not subject humans to any form of embarrassment, bodily harm, and psychological harm.

i'd say that the moon rock is about 2.2 billion years old.