prophase
Further genetic variation comes from crossing over, which may occur during prophase I of meiosis. In prophase I of meiosis, the replicated homologous pair of chromosomes comes together in the process called synapsis, and sections of the chromosomes are exchanged.
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Answer:
C. Producing gametes for sexual reproductive purposes
The nitrogenous bases placed in between the DNA double helix strands, like rungs on a ladder, are positioned there because of the hydrophobic effect and are stabilized by hydrogen bonding. The stability of DNA also relies on the interactions between the hydrogen bonds between bases, hydrogen bonds between bases and surrounding water, and base interaction between neighboring bases.
Hydrogen bonds are able to stabilize the DNA double helix by pairing up with their complementary base pairs (guanine with cytosine and adenine with thymine)
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Cesium is used in the separation of DNA with different densities. Cesium chloride (CsCl) acts as a density gradient for the separation of the DNA (Deoxy ribonucleic acid), and is used in gradient centrifugation.
CsCl density centrifugation:
- CaCl solution is kept in the centrifuge tube along with the DNA sample to be separated.
- The centrifugation causes the solutions to form bands with the denser part at the bottom and the least denser part at the top.
- The DNA with its density similar to a particular layer of CsCl solution density forms a band in that layer.
brainly.com/question/264225
To prevent too much water from getting into the leaves
Guard cells are the only epidermal cells to contain chloroplasts. ... However, in plants that grow in very hot or very cold conditions, the epidermis may be several layers thick to protect against excessive water loss from transpiration. A waxy layer known as the cuticle covers the leaves of all plant species.
