How does the allele that causes sickle cell disease also confer a benefit to humans? A. Mosquitos that bite people with sickle cell disease also contract the disease and die.
B. People with both copies of the sickle cell allele have sickle cell disease but are resistant to typhoid.
C. People with only a single copy of the sickle cell allele do not have sickle cell disease and are also resistant to the parasite that causes
malaria.
D. People with the sickle cell allele have more offspring on average.

How are rocks that cooled within magma chambers found on earth’s surface today? they are pushed up by magma under earth’s surface. they are revealed by erosion of earth’s surface over time. they are pushed to earth’s surface because of their larger size. they are revealed at earth’s surface due to their low density.

Which phrase is the best summary of the model shown? a. the transfer of the sun's energy through trophic levels b. a series of aerobic and anaerobic reactions c. a transformation of light energy into chemical energy d. the breakdown of food molecules

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a.earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c.earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.