Answer:
f
Explanation:
It is variation because not all individuals are the same, and this may be due to the genetics they have
Answer:
brown bear
Explanation:
Brown bears have long, intimidating claws. However, since they are not retractable, they are relatively blunt and are usually used for digging. These bears are incredibly strong, able to break the necks of many large prey with one powerful blow. Their thick fur and layer of fat help to insulate them against the extreme cold temperatures of their habitat.
Answer:
Agriculture and domestication probably started in the Fertile Crescent (the Nile Valley, The Levant and Mesopotamia). ... People probably started agriculture slowly by planting a few crops, but still gathered many foods from the wild. People may have started farming because the weather and soil began to change.
Explanation:
<span>Spleen is also known as the graveyard of RBC, if it helps u
1.Stem cells in bone marrow make all blood cells. RBC lives about 120 days.
RBC are destroyed in Spleen. This process takes place as:
- RBCs are ruptured.
- Heme and globin portions separated.
- Globin > amino acids.
- Iron transferred in transferrin into the blood > into bone marrow for reuse.
- Heme > Biliverdin > Bilirubin > liver >small intestine.
2.Reticuloendothelial cells participate in the destruction of senescent RBC's. The spleen is a well suited site of RBC destruction given that cells must course through 2-3 micron apertures in the walls of splenic sinusoids, which is an ultimate test of cell pliability. Rigid cells are entrapped and phagocytosed. Intra-erythrocyte inclusions are removed during splenic circulation.
Destruction of RBCs happens within reticuloendothelial cells – NOT in the circulation. Globin and heme get recycled, porphyrin is degraded to bilirubin which is conjugated by the liver and excreted in the gut. Rate limiting step is conjugation. Indirect (unconjugated) bilirubin is result if this doesn’t happen.
Normally ~10% RBCs lyse while in circulation Þ Hgb gets released into circulation and rapidly disassociates into alpha and beta dimers which are bound by haptoglobin. The Hgb/haptoglobin complex is transported to the liver. If haptoglobin is depleted, free Hgb circulates and is filtered by the kidney. Free Hgb is either reabsorbed by renal tubular cells or excreted as free Hgb in the urine.
3. Another site reported that
RBC destroyed in liver and spleen, by macrophages. 2 million destroyed per second.
Hb is released and iron is recovered and returned to bone marrow.</span>
