It is a substance that takes part in and undergoes change during a reaction
Answer :
The animals are categorized into 2 groups - eukaryotes and prokaryotes. The microbes like bacteria are coming under prokaryotes. They are unicellular organisms and without a true nucleus.
Viruses are the connecting link between the living and non - living. They are smaller than bacteria. The microbes less than 100 micrometer can't be seen by the naked eye. They can only visible under a microscope.
Viruses like polio, flu virus sizes are 10nm. But some of the viruses are also less than 10nm. The size of bacteria is 1 micrometer. The viruses are 10 times smaller than the bacteria.
The eukaryotic organisms are more advanced and multicellular. Their cell size is larger than bacteria and viruses. The red blood cells under the light microscope are 8 micrometers. The typical animal cells like sperm are 60 micrometers and a skin cell is 30 micrometers. The plant cell for example pollen is 90 micrometers.
The eukaryotic cells sizes are more than prokaryotes like bacteria.
Meiosis is referred to as reduction division as it divides the chromosome number in half. Crossing over or recombination is the main reason of shuffled genes and increased genetic variation in gametes in meiotic cell division as the homologous pairs are paired up during prophase.
<h3>What is crossing over?</h3>
Crossing over is referred to as the exchange of genes of DNA between paired homologous chromosomes. It actually occurs during the development of egg and sperm cells i.e., during meiosis.
It is an enzyme-mediated step, in which the exchange of genetic material takes place between non-sister chromatids of homologous chromosomes.
It actually occurs at the pachytene stage of prophase I of meiosis cell division.
Thus, it can be concluded that the crossing over is the main reason of shuffled genes and increased genetic variation.
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<span>Homologue </span>pairs separate during a first round of cell division, called meiosis<span> I. Sister chromatids separate during a second round, called </span>meiosis<span> II. ... In </span>each round of division, cells go through four stages: pro-phase, meta phase, ana phase, and telophase.
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Answer:
spindle
Explanation:
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