Red blood cells are disc shaped. It is thought one factor that allows them to have this shape is because they do not have a nucleus. This tends to increase amount of space inside the cell for hemoglobin.
They have a flexible disc shape which helps increase the surface- to- area volume ratio which enables oxygen and carbon dioxide to diffuse across the red blood cell's plasma membrane more readily.
Their disc shape also enables them to squeeze through tiny capillaries that are half their size .
<span>Cells control cell division in order to maintain normal cell function. If something happens to the control of the cell division, the healthy cells will divide uncontrollably. These new cells are cancer cells. </span>
The mutations in three genes are responsible for development of cancers:
1. Mutation in proto-oncogenes. Proto-oncogenes normally signal cells to grow and differentiate. Proto-oncogenes can become oncogenes due to mutations which result in the uncontrollable division of the cells.
2. Mutation in tumor suppressor genes. In normal cells, tumor suppressor genes suppress genes essential for cell cycle and that way they prevent uncontrollable cell division. However, after a mutation in these genes, suppression is lost and the cell may progress to cancer.
3. Mutation in stability genes. In normal cells, they have no role either in cell death or growth, but they control mutation rate. Mutation in stability genes results in situation where all genes, including proto-oncogenes and tumor suppression genes, are more frequently mutated.
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For specification to occur, two new populations must be formed from one original population, and they must evolve in such a way that it becomes impossible for individuals from the two new populations to interbreed.
idk if this helps but i tried lol and no need for brainliest
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The correct answer to 153 is "When a cricket player is running fast in pursuit of a ball in the field, intuitively, this motion requires the movement of the legs or the lower limbs of the human body. The lower limb contains 30 bones-namely the femur, patella, tibia, fibula, tarsal bones, metatarsal bones, and phalanges". The correct answer to 154 is "gliding joint-between zygapoheses of successive vertebrae"
