Which best describes fetal development? The heart beats and is heard during the first trimester.
The heart beats and is heard during the second trimester.
The heart beats during the first trimester, but is heard in the second trimester.
The heart beats during the second trimester, and is heard in the third trimester.

Why are adults bigger than they were as children biology

Researchers randomly divide participants into groups. each group takes a different amount of omega-3 fatty acid supplements daily for a month. one group receives a placebo. the researchers measure the impact on cholesterol levels in the blood. what is the purpose of random assignment in this experiment? a, to produce treatment groups with similar characteristics b, to ensure that all people with high cholesterol have an equal chance of being selected for the study c, to increase the accuracy of the research results and prevent skewness in the data

Amoeba sisters video recap pedigrees