White blood cells help to fight off infection and then begins to repair the wound. This would take about 2-5 days to start healing
Explanation:
Scientists didnt belive that there are cells untill robert hooke (1665). He observed the cells in a cork slice with the help of a PRIMITIVE microscope
Leeuwenhoek (1674), with the help of an improved microscope, discovered free living cells in pound water for the first time.
It was robert brown in (1831) who discovered the nucleus in the cell.
Purkinjie in 1839 coined the term 'protoplasm' for the fluid substance of the cell.
THE CELL THEORY, that all plants and animals are composed of cells and that the cell is the basic unit of life, was presented by two biologists, schleiden (1838) and schwann(1839). The cell theory was fuether expanded by virchow (1855) by suggesting that all cells aris form PRE-EXISTING cells. With the discovery of the electron microscope in 1940,it was possible to observe and understand the complex structure of the cell and its various organelles.
Well, thats the history of the discovery of cells.
Answer:
9:3:3:1
Explanation:
If alleles of two genes separate randomly during anaphase-I of meiosis, some new combinations of the alleles are formed in the gametes. A heterozygous genotype for two loci (let's support TtRr) produces a total of four types of gametes in 1:1:1:1 ratio (TR, Tr, tR, and tr). The random fusion of these gametes from two double heterozygous parents (TtRr x TtRr) gives a phenotype ratio of 9:3:3:1. Here, 9/16 F2 progeny exhibit dominant phenotype for both loci while 1/16 exhibits recessive phenotype for both the genes. Rest 3/16 and 3/16 F2 progeny express dominant trait for one gene and recessive for the other.
The zygote must contain genetic information from the mother and from the father, so the gametes must contain half of the chromosomes found in normal body cells.
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