Though the lockdown has undoubtedly had somewhat of a negative impact on certain acpects of our society, there’s no denying that our environment has seen certain benefits since we’ve tucked ourselves away in our homes. According to the Earth Observatory at NASA, satellites have detected decreased levels of air pollution as well as carbon monoxide emission. This is attributed to the closure of most industries as well as the lack of cars and other transportation on the road. Though it isn’t just the air we’re beginning to notice changes in- for the first time in a very long time, the canals in Venice are crystal clear. With fewer boats and tourists about, the water is free of pollution for the first time in centuries. With these facts in mind, I can safely say that I believe the lockdown has definitely positively benefited the environment, but it’s up to us to keep it that way once it ends.
Every cell of the organism has the same DNA sequence and same genes. However, not all genes are expressed in every single cell at the same time. Only those genes necessary for a specialised function of a specialised cell are expressed in the specialised cell. For example, skin cells have some different proteins than nerve cells. Genes responsible for those "skin proteins" are activated in skin cells and are turned off in nerve cells.
Each sieve tube element is normally associated with one or more nucleated companion cells, to which they are connected by plasnodesmata (channels between the cells). Each companion cell is derived from the same mother cell as its associated sieve tube member. Sieve tube members have no cell nucleus, ribosomes, or vacues. Thus, they depend on companion cells to provide proteins, ATP, and signalling molecules
The reduction in chromosome number occurs during <u>meiosis I.</u>
Chromosomes are long molecules of DNA that contain some or all of an organism's genetic material. In most chromosomes, very long, thin strands of DNA are coated with packaging proteins. In eukaryotic cells, the histones are the most important of these proteins.
Within the nucleus of all cells, DNA molecules are packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly wrapped many times around proteins called histones that support its structure.
Another type of cell division, meiosis, ensures that humans have the same number of chromosomes from generation to generation. This is a two-step process in which the number of chromosomes is halved from 46 to 23 to form sperm and eggs.
Learn more about chromosomes here:-brainly.com/question/11912112
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