Among protostomes, which morphological trait has shown the most variation?
A) type of symmetry (bilateral vs. radial vs. none)
B) type of body cavity (coelom vs. pseudocoelom vs. no coelom)
C) number of embryonic tissue types (diploblasty vs. triploblasty)
D) type of development (protostome vs. deuterostome)
Answer: B
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The evolutionary process whereby an ancestral species undergoes speciation and produces two descendant species,
both distinct from their common ancestor, is known as ____.
a. gradualism b. equilibrium c. taxonomy d. anagenesis e. cladogenesis
Life originated in the _____
Fill in the blank(s) with correct word
Your student is trying to create a "Gene X" knockout mouse by introducing a recombinant construct into embryonic stem (ES) cells, selecting transformants, and introducing the transformed cells into mouse blastocysts
He designed his construct as follows: NeoR----region of homology to Gene X---HSV tk--- region of homology to Gene X where NeoR is the neomycin-resistance gene and HSV tk is the Herpes Simplex virus thymidine kinase gene. He transforms the ES cells and exposes them to G418 and ganciclovir. Explain to your student he failed to recover transformed ES cells.
Which of the following is mismatched?
A) Corynebacterium — gram-positive rod B) Mycobacterium — acid-fast rod C) Mycoplasma — gram-positive pleomorphic rod D) Bordetella — gram-negative pleomorphic rod E) Haemophilus — gram-negative rod