every cell has work to do but different cells may have different jobs in multicellular organisms, cell with the same type of job often work together. These group of specialized cell from tissue in turn, tissue often group together to form larger units called organs the heart is an organ; so is the stomach.
Pure water is very close to a pH of 7. The Great Salt Lake (from what I've read about) can range from 8.2 to 7.7 in different areas. Saliva is between 6.5 and 7.5. And ammonia has a pH of 11.
So the items that have a pH between 5 and 8 are pure water, saliva, and possibly the Great Salt Lake.
Answer:
AZT is a thymidine analog
Explanation:
Azidothymidine (AZT) is an antiviral drug used for the treatment of the Human immunodeficiency virus infection (HIV/AIDS) by preventing the transmission of HIV from infected cells. AZT is capable of suppressing the activity of the enzyme reverse transcriptase of the retroviral HIV genome, which enables it to copy RNA into DNA. In infected cells, this double-stranded DNA is integrated into the host genome which is then instructed to produce identical HIV copies. AZT is a thymidine analog that is incorporated into DNA and thus interferes with DNA synthesis, thereby inhibiting cell proliferation.
Answer:
B) increased exchange surface provided by their membranes
Explanation:
Alveoli are tiny air sacs that are responsible for exchanging oxygen (O2) and carbon dioxide (CO2) in the lungs. Alveoli have elastic fibers in order to expand and recoil depending on the volume of air breathed in. The alveolar epithelial cells (pneumocytes) may adopt a shape that serves to increase the surface area of gas exchange. On the other hand, intestinal epithelial cells have microvilli, which are microscopic projections in the plasma membrane. Microvilli serve to increase the cell's surface area, thereby facilitating the absorption of nutrients and water.
