A company develops a new weed-killing chemical. When the chemical is first used, it kills nearly all the weeds. Which statement explains why after 10 years, nearly all the weeds can tolerate the chemical and survive?

A. At first, most of the weeds were sensitive to the chemical. Only the few weeds that were resistant to (or could tolerate) the chemical survived and reproduced, passing on traits that helped them survive.
B. At first, none of the weeds were resistant to the chemical. Over time, a few of the weeds became resistant to (or could tolerate) the chemical survived and reproduced,

Question

A company develops a new weed-killing chemical. When the chemical is first used, it kills nearly all the weeds. Which statement explains why after 10 years, nearly all the weeds can tolerate the chemical and survive?
	
A. At first, most of the weeds were sensitive to the chemical. Only the few weeds that were resistant to (or could tolerate) the chemical survived and reproduced, passing on traits that helped them survive.
B. At first, none of the weeds were resistant to the chemical. Over time, a few of the weeds became resistant to (or could tolerate) the chemical survived and reproduced,