<span>a. Fish have a single central heart; earthworms have several hearts.
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Multi cellular organisms are made up of billions of cells each specialized to a unique role and these cells are organized into structural and functional units such as tissues and organs.
For each cell and organ to function optimally, it requires oxygen and nutrients and needs carbon dioxide and metabolic waste taken away in a continuous, never ending process.
<span>A mechanism is needed to accomplish the important function of transporting the relevant materials to and from the cell. The circulatory system fits this bill splendidly. It is a specialized organ system which allows blood and lymph to flow through the entire body carrying nutrients such as glucose, amino acids and electrolytes as well as oxygen to each cell, at the same time carting away carbon dioxide and all sorts of metabolic waste over to excretory organs to be expelled from the body.
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Answer: D. It yields chromosomes that contain both maternal and paternal DNA.
Explanation:
The recombination or crossing over is a genetic process. It takes place during the Prophase I of meiosis. The homologous pair align and held together by synapsis. This results in the mixture of genes combination formed from both parents that can be represented as a single chromosome.
If the recombination do not occur then each chromosome will be either 100% maternal or paternal. Thus recombination assures the recombinant chromosomes which consists of genetic material from both parents. Thus the genetic diversity of offspring increases.
Answer: The most affected would be organs that have QUICKLY dividing cells (like the intestine and hair follicles).
Explanation:
Cancer cells are cells that divides uncontrollably giving rise to a mass of tissue called tumour. They grow faster than a normal cell in an uncoordinated manner, and continues to grow after the initial stimulus has ceased.
Paclitaxel is a drug that is approved for the treatment of cancer affecting different parts of the body. It's a microtubule-stabilizing drug whose mechanism of action is to induce mitotic arrest in the cancer cells.
Paclitaxel in its cause of action not only affect cancer cells but normal cells as well. To justify this statement, as stated earlier, the mechanism of action of paclitaxel is to induce mitotic arrest. Therefore the cells of organs where rapid mitosis occurs would be most affected. Skin cells, hair follicles and the cells lining our intestines (epithelial cells) all have high rates of mitosis as these tissues constantly need to be replaced.
Only certain species ofmosquitoes of the Anopheles genus—and only females of those species—can transmitmalaria. Malaria is caused by a one-celled parasite called a Plasmodium. Female Anopheles mosquitoespick up the parasite from infected people when they bite to obtain blood needed to nurture their eggs.
after meiosis I, the number of chromosomes is half that of a somatic cell.
