The gray crescent region of the amphibian zygote is thought to contain:a
growth factors and developmental determinants.
b. hormones and ribosomes.
c. yolk and dark pigment granules.
d. mitochondria and ribosomes.
e. neurotransmitters and hormones.
A
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Which of the four nucleotides are typically methylated in "islands," resulting in closed chromatin structure?
What will be an ideal response?
Scientists using evolutionary systematics to construct a phylogenetic tree would use:a
a combination of ancestral and derived characters. b. the number of shared characters the organisms posses. c. primarily polyphyletic groupings. d. only derived characters. e. only ancestral characters
The present range of the sugar maple in North America extends from the Atlantic Ocean west to the Mississippi River and from southern Ontario, Quebec, and New Brunswick south to Tennessee and Virginia
If the global temperature rises 10°C in the future, where will the range of sugar maples be found? A) Farther west B) Farther south C) Farther north D) In the same place; global warming will not affect the heat tolerance of plants. E) Nowhere; sugar maples will become extinct.
The virus that causes rabies travels up nerve cells to the brain and spinal cord. Which cell structures will allow the virus to move through the nerve cells?
A) pseudopods B) Golgi complexes C) nuclei D) microtubules