By definition, a sympatric speciation is a biological process wherein the evolution of a certain species most likely comes from their single ancestral species. Its main difference from the allopatric speciation is that the evolution does not necessary require to be physical in nature, therefore, it is most likely to occur less frequent.
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Cycads /ˈsaɪkædz/ are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, therefore the individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow very slowly[3] and live very long, with some specimens known to be as much as 1,000 years old.[citation needed] Because of their superficial resemblance, they are sometimes mistaken for palms or ferns, but they are not closely related to either group.
Cycads are gymnosperms (naked seeded), meaning their unfertilized seeds are open to the air to be directly fertilized by pollination, as contrasted with angiosperms, which have enclosed seeds with more complex fertilization arrangements. Cycads have very specialized pollinators, usually a specific species of beetle. Both male and female cycads bear cones (strobili), somewhat similar to conifer cones.
Cycads have been reported to fix nitrogen in association with various cyanobacteria living in the roots (the "coralloid" roots).[4] These photosynthetic bacteria produce a neurotoxin called BMAA that is found in the seeds of cycads. This neurotoxin may enter a human food chain as the cycad seeds may be eaten directly as a source of flour by humans or by wild or feral animals such as bats, and humans may eat these animals. It is hypothesized that this is a source of some neurological diseases in humans.[5][6]
Cycads all over the world are in decline, with four species on the brink of extinction and seven species having fewer than 100 plants left in the wild.[7] The plant has a very long fossil history, with evidence that they existed in greater abundance and in greater diversity before the Jurassic and late Triassic mass extinction events.
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Answer: The atom of carbon is able to form macromolecules because it has only four electrons in its outer shell. This is the reason why it can bond with four other carbon atoms. The bonds that it forms with other carbon molecules are very stable.
Explanation: I did my research and i also took Science class. :)
Hope this Helps :).
Two five dollar bills = ten dollars
10+10+10+10=40+286=326
<span>An organelle is a functional subunit enclosed by a membrane within a eukaryotic cell. The name "organelle" means little organ and the name comes from the analogy with organs: what an organ is to a body, an organelle is to a cell. So, the organelle is the organ of the cell. There are different types of organelles in cells, such as nucleus, mitochondria, Golgi apparatus, endoplasmic reticulum, chloroplasts, vacuoles, and they all have a different function. For example, the nucleus is the organelle which main function is control of cell activities. Mitochondria are organelles which main function is energy production. </span>