The monomers that compose nucleic acids are called . The three parts that make them include a phosphate group, a nitrogen containing base, and a .

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.

Researchers determine that the biodiversity in a woodland region is declining. they identify two major threats to the region's biodiversity, a method to address each threat, and the expected outcome of each method. this information is shown in the table. threat method number of species that benefit number of years to see benefit habitat fragmentation reforestation 450 8 introduced prey species biological augmentation 150 2 which statement is an accurate explanation of the information in the table? a. biological augmentation would benefit only a few species because it is typically not very effective. b. biological augmentation would take less time to be effective because it targets the majority of prey species. c. reforestation would take the longest time to be effective because trees take several years to grow. d. reforestation would not benefit many species because most forest species live on the ground.

Which type of respiration takes place when there is no oxygen present? a. anaerobic b. mitochondrial c. cellular d. aerobica. anaerobic