The 19th, 24th, and 26th amendments were all important additions to the constitution because they
a) passed through congress unanimously.
b) addressed the issue of congressional representation.
c) eradicated the remaining institutions of legal racism in the south.
d) expanded the democratic ideal to include more of the u. s. population.

Thecorrect answer is D, beacuse if you read the question it makes more sense

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.