The use of pesticides and herbicides is carefully monitored because of the effect they can have on the environment. Which of the following is a possible negative effect of the use of these chemicals on the environment?
a
b
OO
Runoff carries these chemicals into lakes and streams
These chemicals are expensive to produce
Storage space for these chemicals is limited
These chemicals cannot be purchased in large bulk
C С
c
d

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Which sentence is an example of a strong conclusion to an autobiography? a. i stayed after school three days in a row to practice onstage in the auditorium. b. i knew i would have to practice all week to memorize my dance for the recital. c. after the recital was over, i knew practicing was worth it, and i was looking forward to my next big challenge. d. on opening night, i danced in front of a packed auditorium.

Which phase of the cell cycle ensures that identical copies of the dna are made for daughter cells?