Why do harmful agents cause the most severe birth defects during the embryonic period?

A) This is a period of rapid differentiation when cells and tissues acquire specific functions and organs form.
B) This is the period when substances pass most easily through the placenta.
C) The mother's hormones are at the highest levels at this time.
D) The embryo has not yet implanted into the uterus.


A

Biology & Microbiology

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A microbiologist inoculates Staphylococcus aureus into a culture medium. Following incubation, both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture. What is the most likely explanation?

A. The microbiologist used too much inoculum. B. The incubation temperature was incorrect. C. The culture medium must be selective. D. The culture is contaminated. E. The culture medium must be differential.

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An organism that many women carry as part of their normal genital microbial flora that may be transmitted to the neonate during childbirth is:

a. Staphylococcus. b. Escherichia coli. c. S. agalactiae. d. G. vaginalis.

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In which stage of the cell cycle is G0 located?

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Biology & Microbiology