Ted and Rosa rushed to the hospital, ready to welcome their new baby soon. But within a few hours, they were driving home again. It turns out they were fooled by Rosa's .

Braxton-Hicks contractions

Explanation:

Braxton-Hicks contractions is also known as false labor pain, as in this phenomena woman uterine muscles contract  which usually consider as labor pain , but in reality  it just like menstrual cramps, due to which pregnant women feel uncomfortable.

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.        

the first two-party system consisted of the federalist party, who supported the ratification of the constitution, and the democratic-republican party or the anti-administration party (anti-federalists), who opposed the powerful central government, among others, that the constitution established when it took effect in