Secondary xylem and phloem are produced by the _________.
A. Heartwood
B. Vascular cambium
C. Cork cambium
D. Sapwood
E. Bark
Ans: B. Vascular cambium
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If a pair of homologous chromosomes fails to separate during anaphase of meiosis I, what will be the chromosome number of the four resulting gametes with respect to the normal haploid number (n)?
A) n + 1; n + 1; n - 1; n - 1 B) n + 1; n - 1; n; n C) n + 1; n - 1; n - 1; n - 1 D) n + 1; n + 1; n; n E) n - 1; n - 1; n;n
A technique that separates a readable pattern of DNA fragments is
A. gel electrophoresis. B. biotechnology. C. gene probes. D. recombinant DNA. E. genetic engineering.
Chemoautotrophs __________.
a. oxidize inorganic substances for energy and use CO2 as a carbon source b. are photosynthetic c. use organic molecules for both energy and carbon sources d. use light to generate ATP but need organic molecules for a carbon source e. require glucose
Antibiotics are derived from all of the following, except ________.
A. Penicillium B. Bacillus C. Staphylococcus D. Cephalosporium E. Streptomyces