In early vertebrate embryonic development, a number of pathways, such as Wnt, Hedgehog, and Notch, regulate differentiation and organ formation. They operate by __________
A) formation of new transcription factors at each stage
B) transcription activation due to interaction among transcription factors
C) cell signaling mediated by receptor binding
D) establishing anterior-posterior and dorsal-ventral symmetry
E) stimulating MADS box genes
C
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Your cat has fleas! You look at the ingredients in the flea control ointment, and see that it contains methoprene, a juvenile hormone analog. What does this accomplish?
Many insecticides target insect hormones such as juvenile hormone or ecdysone to disrupt development. This is preferable to simply killing the insect with more broadly-acting toxins. A. prevents flea larvae from maturing B. kills juvenile fleas C. reinvigorates the cat's immune system, to repel the fleas D. forces juvenile fleas to mature early, disrupting development of reproductive organs Clarify Question What is the key concept addressed by the question? What type of thinking is required? Gather Content What do you already know about juvenile hormone? What other information is related to the question? Choose Answer Given what you now know, what information is most likely to produce the correct answer? Reflect on Process Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Most antipsychotic medications act by blocking _________ receptors.
A) serotonergic B) dopaminergic C) cholinergic D) muscarinic
The two nitrogen atoms in nitrogen gas (N2) share six electrons forming a ________.
A. double bond B. single covalent bond C. hydrogen bond D. triple covalent bond E. double covalent bond
Which of the following are NOT members of cnidaria?
A. sea anemones B. corals C. hydrozoa D. sponges E. Portuguese man-of-war