What type of bonds joins amino acids together

Asap! how does the distance between two objects affect the force of gravity? how is the moon dependent on the sun?

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.

During which phase does earth see more than half of the moon's surface? 1)first quarter2)third quarter3)waxing gibbous4)waning crescent