Which of these describes something that would increase the validity of an experiment?

a) having no dependent variables

b) having a single experimental group

c) having other scientists repeat your results

d) having to enter your experiment in a science fair

B

Explanation:

Most experiments require a control group AND one experimental group.

C) having other scientists repeat your results

Explanation:

The fact that other scientists repeat an experiment will increase the validity of it, since the probability of an error will be lower due to a bad measured coming from a single scientist.

For example, in the release of the first image of a black hole. Some different groups of scientists treated the data using different methods to get that image, and all of them reached the same result.

r = ρ x length / area  

ρ = r x area / length  

ρ is in ohm-meters  

in basic units, it is m³kg/s³a²  

i think this is it.