Which of these might have been observed in the common ancestor of chondrichthyans and osteichthyans?
A) a mineralized, bony skeleton
B) opercula
C) a spiral valve intestine
D) a swim bladder
A
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Which one of the following is true of the sporophyte stage of a flowering plant?
A. It is haploid. B. It is 1N. C. It is a nonphotosynthetic stage. D. It is the obvious stage such as an oak tree. E. It is dependent on the gametophyte for nutrition.
Answer the question using the accompanying figure. The constant region of a light chain is indicated by number____
a. 1 b. 2 c. 3 d. 4 e. 5
The home range of an animal is always defended
Indicate whether the statement is true or false
By definition, if the DNA of a cell undergoes a spontaneous mutation, is was NOT due to ________.
A. spontaneous depurination of nucleotides B. insertion of transposons C. exposure to radiation D. errors in DNA replication