Answer:
D, think of chemical changes. When iron rusts it is chemically changed. The other answers are a change in form or a property of iron.
(15) Label 1 is D
(16) Label 2 is A
(17) Label 3 is B
(18) Label 4 is C
Answer:
No 15N/15N labeled DNA was observed in second generation
Explanation:
Meselson and Stahl were doing an experiment to find out the semi-conservative mode of replication of DNA. The first cultured bacteria in 15N medium which was containing a heavy isotope of nitrogen. The DNA synthesized here had more density. After that they transferred the bacteria to the 14N containing medium. When bacteria reproduced and new strands of DNA were synthesized, they observed the following -
- The first generation had hybrid DNA with 15N/14N strands
- The second generation had both hybrid 15N/14N DNA and 14N/14N DNA strands
- There was no 15N/15N DNA observed.
In this way they proved that one strand of DNA is kept conserved during the replication.
Answer:
Try B. C and D are helping stop global warming and A isn't as much of a factor
