The important point is that the surface area to the volume ratio gets smaller as the cell gets larger and as volume increases, surface area to volume ratio decreases. The larger a cell, the less easily it can get rid of waste and it also has more trouble getting water, nutrients and gases in. That is why we do not see giant cells. Instead we see multiple cells in larger organisms.
One way to increase surface area is to flatten the cell. That is why red blood cells are flat discs, instead of spheres. Another way is elongation. That is why many bacteria are rod shaped, and why neurons are elongated. In fact, the human body relies on the same principle to adapt to climate. Long tall and lean folks with long arms and legs live in East Africa, because such shapes increase surface area to get rid of excess body heat to avoid heat strokes. Europeans and Asians adapted to cold climates, in contrast, have shorter arms and legs and rounder torsos to minimize surface area. to conserve body heat.
Answer:
The correct answers are A, C and D.
Explanation:
Dialysis is a treatment given to a patient to maintain his chemical levels in the body salt. Dialysis is a treatment which removes the Extra water, wastes, salts from the patient's body. This treatment is given to the patient in case of the failure of the Kidneys which are unable to clear the body from the wastes and toxins naturally. This is a time consuming process which uses a machine to purify blood from wastes and toxins. It is not the permanent solution for the renal failure, tough it is a good temporary solution.
Mantle convection causes tectonic plates to move around the Earth's surface.
Answer:
The correct option is A. Polycythemia Vera
Explanation:
Polycythemia vera is a myeloproliferative disorder of bone marrow hematopoietic cells that causes excessive production of all types of blood cells.
Primary erythrocytosis occurs as a result of polycythemia vera, in this myeloproliferative disorder the bone marrow produces too many red blood cells along with excessive amounts of white blood cells and platelets. Bone marrow under normal conditions produces blood cells and contains the precursor cells of the three series: red blood cells, white blood cells or leukocytes and platelets or thrombocytes, this disorder is characterized by excessive or uncontrolled proliferation or growth of these cells. The increased production of red blood cells or erythrocytes is called erythrocytosis.
