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.

Aneuron is stimulated with an electric pulse. the action potential is detected at a point 3.70 cm down the axon 0.0052 s later.when the action potential is detected 7.20 cm from the point of stimulation, the time required is 0.0063 s. what is the speed of the electric pulse along the axon? (why are two measurements needed instead of only one? )

What drives an advertising campaign?

Brepresent the dominant allele for brown fur, and b represents the allele for white fur. if two rabbits with the genotype bb reproduce, what are the possible phenotypes for their offspring