Use the drop-down menus to complete the statements.
Each organism in a population produces more offspring than can survive. This is called . In order for natural selection to occur, populations must have . When the environment changes, nature selects favorable . Over time, these in a population.

answer; /// i believe that the correct answer is; ///a combination of the birth and death

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation:

the answer would be..

b. sucking

c. heat from the poles back down towards the equator.