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.
Answer:
aortic arches (earthworms)
Explanation:
Earthworms vessels link together
carbon dating shows how old a bone is by measuring the amount of carbon 12, and carbon 14 that the bone contains. and because carbon 14 is not replaced by exchange with the atmosphere the ratio of c12:c14 (the ratio of carbon 12 to carbon 14) tells how old the bone is by comparing the amount of carbon 14 to the amount of carbon 12. carbon 14 has a half life of 5,700 years, while carbon 12 is stable and does not radioactively decay at all.
Answer:
The correct answer is ''METAPHASE I.''
Explanation:
Metaphase I is the stage in which chromosomal studies are generally performed, because its morphology is very clear. The chromosomes, moved by the mitotic spindle, are placed in the center, between the two asters and form the so-called metaphase plate, in which the chromosomes are positioned in such a way that the kinetochore of each sister chromatid are oriented towards the opposite poles. Keeping chromosomes on the cell equator implies a balance between the forces of the microtubules that tend to move the kinetochores toward opposite poles, so positioning them in the center involves a great deal of energy.In each kinetochore, between 20-30 microtubules can be anchored, which exert traction force towards the pole from which they come, so the metaphase plate is maintained by the balance between the opposite forces of the poles on the chromosomes, which hold their sister chromatids by centromeric cohesin.
