How are the reproductive cycles of retroviruses and retrotransposons different?
a. Retrotransposons can integrate into a host chromosome.
b. The retroviral genome must be reverse transcribed to DNA.
c. Only retrotransposons can be passed to daughter cells following cell division.
d. Retroviruses have an extracellular phase.
e. Only retroviral genes are transcribed.
Ans: d
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Having aseptate hyphae, members of the phylum ____ are described as coenocytic since they have numerous nuclei in
a common cytoplasm.
a. Glomeromycota b. Basidiomycota c. Chytridiomycota d. Zygomycota e. Ascomycota
Which fungal group is typically multicelled and produces spores in structures called basidiocarps?
a. Ascomycetes b. Chytrids c. Glomeromycetes d. Zygomycetes e. Basidiomycetes
At which stage is a human embryo when it attaches to the endometrium in the uterus?
1.blastocyst
2.gastrula
3.hypoblast
4.morula
In the controlled laboratory experiment with mice and artificial sweetener, one third of the mice receiving sweetener had bladder cancer. Which of the following would be the best conclusion to this experiment?
A. Since two-thirds did not, this proved that there is still no direct cause and effect relationship B. This is a small group (100) and such a result could easily be a random result C. Biological systems are very complicated and results of one third represent an outcome of this complexity;these results give us our best approximation of the likely effects of this sweetener D. Although none in the control group developed cancer, only a small number of cancerous mice would be required to equal the experimental cases, so it is the number control animal that must be increased to be sure it is not a random effect