At what stage of human development would you expect to first see a beating heart? Choose 1
Choose 1

(Choice A)
A
Zygotic stage

(Choice B)
B
Blastocyst stage

(Choice C)
C
Embryonic stage

(Choice D)
D
Fetal stage

Choose the molecule that is described by each phrase. energy used during long activities:

After getting the slide and microscope ready, stella is eager to see the microscopic pond water specimen! she crouches around her microscope and aligns her eye with the microscope’s eyepiece. but she's only able to see a bright white light. at this point, no specimens or cells are visible on stella's pond water slide. after taking a moment to collect her thoughts, stella realizes she can't see any lifeforms because .

Select the word from the list that best fits the definition a system made of 25 satellites