Answer:
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.
Explanation:
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(Jane)
Atherosclerosis refers to the build-up of fats and cholesterol in the walls of blood vessels (Option A).
<h3>What is atherosclerosis?</h3>
Atherosclerosis is a disease characterized by the build-up of fats and cholesterol in the walls of blood vessels.
This build-up of fats narrows the blood vessels, thereby difficulting the movement of blood in the bloodstream.
The symptoms of atherosclerosis include, among others, chest pain, shortness of breath and fatigue.
Learn more about atherosclerosis here:
brainly.com/question/4142223
Nails are made of iron because, iron is strong and sturdy; although nail rust when it undergoes oxidation when expose to water but it is not explosive.
Barium and phosphorus are not suitable for nail making because of their properties.
Barium is an element which reacts with virtually all non metals, forming poisonous products which are dangerous to health and to the environment. It also reacts explosively with water.
Phosphorus is not found in its pure form in nature, it conducts electricity and it is combustible in nature.<span />
Answer:
Thermodynamics
Explanation:
By definition, thermodynamics is the study of energy transformation that occur in a collection of matter.
Scienttist call the theory the big chrunch
