Why did Meselson and Stahl choose to grow E. coli in broths of nitrogen isotopes A. The bacteria's phosphate groups would be replaced by the nitrogen.
B. The nitrogen would be incorporated into deoxyribose.
C. The nitrogen would influence bonding between base pairs.
D. The nitrogen would be incorporated into the DNA nucleotides.

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?

What element is able to combine with itself and hydrogen to form large molecules ?

Refer to this portion of a dichotomous key for fish identification to answer the question. 1. (a) has a single dorsal fin ® 5 (b) has a double dorsal fin ® 2 2. (a) one fin is spiny, the other is smooth ® 3 (b) one fin is not spiny or smooth ® 4 5. (a) has small fin on back near tail ® 6 (b) has no fin on back near tail ® 7 6. (a) has barbs near the mouth ® catfish (b) does not have barbs near the mouth ® 10 7. (a) tail is asymmetrical ® 8 (b) tail is symmetrical ® 9 10. (a) scales are small ® trout (b) scales are large ® whitefish what is the next step to complete to identify a fish that has a single dorsal fin, no fin on the back near the tail, and no barbs near the mouth? step 2 step 5 step 7 step 10