Pesticides are chemicals that are often sprayed on crops to kill plant-eating insects, preventing damage to the crops. WHile pesticides are effective initially, many researchers claim that any single pesticide will see reduced effectiveness in as little as ten to fifteen years. Which of the following best supports the claim by scientists that the pesticides will eventually lose their effectiveness? A. Insects will evolve to avoid any plant sprayed with pesticides to increase their chances of survival.
B. Insects that are naturally resistant to the pesticide will survive and reproduce more than the insects that are sensitive to the pesticide.
C. The insects will build up a tolerance to the pesticides, and eventually the pesticide will not affect them.
D. The pesticides will increase the mutation rate in the insects, resulting in higher genetic diversity and higher survival rate.

A: rachel carson :

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.

Then it is june the conclusion to the second sentence is just restating "if it is june then it is summer"