Imagine that a researcher is comparing the sequence of several protein-coding genes among mice, rabbits, and humans. She finds that, for most of these genes, the rabbit sequences are more similar to the human sequences than are the mouse sequences. What can she deduce?1. Mice and human share a more recent coomon ancestor than do rabbits and humans.2. More sequence are conserved between rabbits and humans than between humans and mice.3. No similar proteins exist in humans and mice.4. Mice and rabbits do not share a common ancestor.5. Humans and mice do not share a common ancestor.

20 the compound al(nh3)2 has atoms of nitrogen.

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.

Which of the following determines the specificity of a dna probe? a. type of radiation b. level of enzymatic activity c. number of neutrons d. complementary base pairing