Which of the germ layers gives rise to most of the internal organ systems?
a. mesoderm
b. ectoderm
c. endoderm
d. both the mesoderm and ectoderm
c. endoderm
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Volvox, a species of ________ algae, lives in spherical colonies joined by thin cytoplasmic strands
a. charophyte b. red c. brown d. chlorophyte
Maternal PKU can result in serious effects in fetuses. This problem occurs because:a
the fetus is homozygous for PKU and therefore cannot metabolize phenylalanine. b. the fetus is usually homozygous dominant and therefore has PKU. c. the mother is heterozygous for PKU and therefore cannot metabolize phenylalanine. d. the mother is homozygous dominant for PKU and cannot metabolize phenylalanine. e. the mother is homozygous recessive for PKU and cannot metabolize phenylalanine.
In tracheophyte plants, water and dissolved minerals are conducted away from roots by
A. water vessels. B. stomata. C. chloroplasts. D. xylem tubes. E. phloem tubes.
The spores that are released when the zygospore splits open are ________.
A. triploid B. haploid C. sterile D. diploid E. motile