All the cells in a person's body have the same DNA and the same genes. However, the difference between cells in different tissues and organs is that the "expression" of the genes differs between cells. Expression means that the message from the DNA is being copied and made into protein.
Answer:
There are two main types of stem cells: embryonic stem cells and adult stem cells.Stem cells provide new cells for the body as it grows, and replace specialised cells that are damaged or lost. They can divide over and over again to produce new cells.
Crossing over is the main event in meiosis and heredity as it leads to genetic variation.
<h3>What is genetic variation?</h3>
Genetic variation is the changes that take place in the genes of individuals that can lead to the formation of new characters.
it generally occurs in meiosis specifically during crossing over.
Thus, it can be concluded that crossing over between non-sister chromatids during meiosis is significant in heredity as it leads to genetic variation.
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<span>As humans change the way we live on the planet, the way that nitrogen moves around the Earth also changes. Nitrogen atoms may seem small enough to be easily overlooked. We look right through the ones in the air, do we not? Yet recent changes in the nitrogen cycle are causing a very noticeable effect on natural environments and human health. Lakes are clogged with aquatic weeds. Dead zones have formed in areas of the oceans where animals can not survive. Air pollutants that contain nitrogen are decreasing air quality and greenhouse gases that contain nitrogen are becoming more common.</span>
There are now 2 cells instead of 1
