Which of the following phyla is a member of the Radiata?
a. Nemertea
b. Porifera
c. Rotifera
d. Ctenophora
e. Echinodermata
D
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A chemoorganotroph and a photoautotroph in the same environment would NOT compete for
A) oxygen. B) carbon. C) nitrogen. D) carbon and oxygen.
The effects of allometric growth on head morphology in the human and chimpanzee
A. The human and chimp fetal skull are exactly the same, the human jaw development slows down after adulthood.
B. Heterochrony is occurring, the chimp jaws continue to develop at a faster rate than human jaws.
C. Paedomorphosis is occurring, the human jaw retains its small size while the chimp jaw continues to grow even in adulthood.
D. The nasal passages of the chimp are shortened due to reduced growth during fetal development while the nasal passages of the human grow through adulthood.
E. All of the choices are correct.
At several points in the cell cycle there are checkpoints that control the cell's passage from one phase to the next. If a cell receives a signal at each checkpoint, it continues to the next phase; if it does not receive the signal, the cell does not
continue. For example, a growth factor may stimulate a cell to move from G1 into S phase. If no growth factor is present, the cell cycle stops in G1 and the cell does not divide. Predict what would happen to a cell and to a multicellular organism if there was a defect at the checkpoint and the cell continued through the cell cycle even in the absence of a signal. What will be an ideal response?
Zinc (Zn) is considered a macronutrient.
Answer the following statement true (T) or false (F)