During days 8 and 9 after fertilization in humans, ____.

A. amnion cleavage begins
B. a blastocyst forms
C. an embryonic disk is formed
D. implantation occurs
E. gastrulation occurs


Answer: D

Biology & Microbiology

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Why are steroids considered lipids?

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What will be an ideal response?

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How does a cell typically know when to divide?

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