Which of the following stabilize the double helix of DNA? A. lonic bonds
B. Phosphodiester bonds
C. Hydrogen bonds
D. Hydrophobic interaction
E. Both B and C
- How does DNA and RNA differ?
A. Type of sugar they contain
B. How many strands they contain
C. By the bases they contain
D. By their function
E. All of theses

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.

Ry was studying two populations of the same species of lizards. one population lived on an island and the other lived on the mainland. both populations were affected by a hurricane that hit the island and the mainland with equal force. a year later, henry was testing the gene frequency and saw a decrease in genetic variation in the island species, but not in the mainland species. which best describes a conclusion he might have reached? gene flow greatly affects small populations, but large populations can recover. genetic drift greatly affects small populations, but large populations can recover. gene flow greatly affects large populations, but small populations can recover. genetic drift greatly affects large populations, but small populations can recover.

Apopulation of black bears depends on salmon from a stream for food. if a drought causes the stream to run dry one year, how will this likely impact the black bear population?