The half-life for DNA decay is 521 years. What does it mean?

A. Half of the organisms used to live for 521 years.

B. Scientists can only find DNA for the last 1042 years.

C. Half the DNA bonds breakdown over 521 years.

D. Scientists can only study organisms that lived 521 years ago or longer.

i think it should be C.

Explanation:

But a study published this week (October 10) in the Proceedings of the Royal Society B estimates that DNA from bone has a half-life of 521 years: after that amount of time, half of the nucleotide bonds that hold it together are broken, and after another 521 years, those bonds are cut in half again, and so on.

a. as the temperature increases, the kinetic energy of the gas molecules increases & the molecules move faster & further away from each other.

b. if you decrease the temperature of a fixed amount of gas at constant pressure, the combined gas law reduces to charles's law. in this case, volume will also decrease.

burning of wood and coal

explanation:

the panel also concluded there's a better than 95 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in earth's temperatures over the past 50 years.