Why could an ultrasound performed at four weeks be unable to determine the sex of a developing
fetus?
What will be an ideal response?
We can see from figure 48.17 of the text that the male and female structures look nearly identical until
around seven weeks. At that point, hormones direct the development of distinctive male or female
reproductive structures, which would later be identifiable on a sonogram.
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A researcher determined that a strain of E. coli is producing a shortened version of a protein required for glucose metabolism. What type of mutation could be responsible for this shorter than normal protein?
A. nonsense mutation B. missense mutation C. silent mutation D. sense mutation E. frameshift mutation
Which of the following statements describes mycorrhizae?
A. A mycorrhiza is a mutualistic relationship between fungi and the roots of most plants. B. A mycorrhiza is a parasitic relationship between bacteria and the roots of most plants. C. A mycorrhiza is a mutualistic relationship between bacteria and the roots of most plants. D. None of these statements describes a mycorrhiza.
Binary fission is a form of sexual reproduction in which the daughter cells have a different genetic combination than the parent cell.
Answer the following statement true (T) or false (F)
A distinctive feature of spirochetes is the presence of
A. endoflagella. B. nucleosomes. C. fimbriae. D. variable surface antigens. E. helically arranged pili.