The fossil records of primitive plants show a variety of seed dispersal mechanisms that has been adopted by plants at various stages and how they have evolved. The most primitive of this seed dispersal mechanism is the Anemochory
Anemochory is the dispersal of seed through the wind. The seeds have wing like structures and are lightweight to be able to fly away with the wind. They are dull colored and are pale that will prevent the seed from being visible.
Hydrochory is the next order of evolution of the seed dispersal mechanism which became majorly adopted by plants that tend to grow near water sources and those whose seeds are too heavy to fly in the air. One of the best examples is the coconut that falls off on the sea water in the coastal areas and floats to other lands and sprouts to a new plant.
Barochory is the dispersal of the seed through gravity. This is the mechanism where the fruit falls off to the ground due to gravity and grows into a new plant.
Endozochory is the dispersal of the seed through animals. In this case the seed is usually covered with a fleshy edible part which is consumed by the animals and in this process the seed goes into the digestive system of the animal and is excreted in a different place from where the seed can sprout into a new plant.
Ballochory is the dispersal of the seed due to the forceful ejection of the seed by explosive dehiscence of the seed. This lets the plant to place its seeds in a distant area. One of the best examples is the Hura Crepitans which is also called the dynamite tree, named after its exploding fruits.
The answer is d) organic chemistry
The effect Colchicine might have on dividing cells is that the duplicated chromosomes might not be able to segregate into daughter nuclei.
Colchicine is an alkaloid that attaches to tubulin and prevents it from polymerization to microtubules. As we know that Microtubules are a component of the cytoskeleton of a cell that aids in molecular mobility inside the cell.
During cell division, chromatin condenses into chromosomes, which are then connected to microtubules. The chromosomes are separated into daughter cells by microtubules.
When these cells are treated with colchicine, tubulin polymerization to microtubules may not occur, and the chromosomes containing daughter nucleic might not be separated.
Learn more about chromosomes here:
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A gateway substance is something that may be menial but could lead to something bigger, an example is weed in the drugs world, weed is not hard to get and is usually a gateway drug to stronger types of drugs and potentially more dangerous
Answer:
Firstly, the partial pressure of nitrogen (78%) is crucial to breathing purposes. Without this pressure, the lungs will burst and animals cannot survive.
Secondly, nitrogen is required for the formation of amino acids (building blocks of proteins) and other organic compounds that are necessary for the survival of living organisms. Principally, in the atmosphere, nitrogen is present in the form of molecular nitrogen (N2). N2 is fixed by nitrogen-fixing bacteria that form nitrates and nitrites. These molecules are then used in biochemical processes to produce proteins (amino acids) and other organic compounds. In the absence of nitrogen, these processes could become seize of limited significantly thus affecting life overall.
Thirdly, nitrogen and its derivatives act as greenhouse gases that maintain the Earth's temperature within a range that supports life. Yes, the increased abundance of nitrous oxides is not good because of acid rain and other issues, however, still, the presence of nitrogen is important for life on this planet.
