During prophase I, all four chromatids of the two homologues become closely associated as a result of pairing, forming a structure known as a tetrad or bivalent.
<h3>What is a tetrad?</h3>
A tetrad is a structure formed during the prophase I stage of meiosis I whereby two homologous chromosomes pair together.
Meiosis occurs in two stages of division namely;
- meiosis I
- meiosis II
In meiosis I, homologous chromosomes are separated but are first paired during the prophase stage to form the tetrad or bivalent structure.
Therefore, during prophase I, all four chromatids of the two homologues become closely associated as a result of pairing, forming a structure known as a tetrad or bivalent.
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Answer: Humans
Explanation: There were once wild, but then got used for labor and stuff.
A.
Tight junctions are <u>cell junctions in areas that are subjected to great mechanical stress, such as the skin and heart muscles</u>
Explanation:
They are also called <u>exclusion junctions</u>. This is because they form very tight junctions between adjacent cells such that only very small molecules, like ions, can pass in between the intercellular spaces of the cells. This is why they are found in regions where very little leakage is needed such as the heart -where blood could leak out during pumping- or the skin where foreign material cannot be allowed into the body.
They are also favorable in high stress regions because they bound cells together giving them structural integrity because they limit the movement of cells and their membrane intergral proteins.
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Answer:
4.Only DNA serves as the master copy of an organism's genetic code which must be replicated by unzipping and base pairing before the cell divides.