Thick- skinned rhinoceroses and elephants were once classified together as pachyderms (meaning "thick skin"). They actually descended from different ancestors that in turn evolved from a thin-skinned common ancestor that was not included in the pachyderms. Pachyderms were therefore, as a taxon,
A. monophyletic.
B. paraphyletic.
C. a kingdom.
D. polyphyletic.
E. a supergroup.
Answer: D
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How many net ATP are generated in aerobic respiration?
a. two b. eight c. 10 d. 32 e. 36
Humans have the diploid number of chromosomes, 2n = 46. This also indicates humans
A. have two genomes. B. are more intelligent than worms. C. have at least two genotypes that can result from fertilization. D. have 23 chromosomes that are necessary for life.
In a multicellular organism, nerve cells are different from muscle cells because
a. each cell type has a unique set of transcription factors and repressors, so it expresses a specific set of genes b. each type of cell within a multicellular organism contains a different set of genes c. random events within each cell regulate the expression of genes and result in different genes being expressed in different cells d. cells gain and lose different genes during embryonic development, so each cell in an adult only has some genes from the original set
When a pregnant woman ingests toxins such as alcohol and nicotine, the embryo is put at risk because these toxins can
A. diffuse from the mother's blood into the embryo's blood within the placenta B. enter the embryo when it eats C. transfer to the embryo since the mother's blood normally mixes with the embryo's blood in the placenta D. enter the uterus through the mother's navel