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:
~Dr.Smiley~
(Jane)
Answer:
Use any of the followin
Explanation:
Thin narrow beak, Two legs, thin tail, wings
Answer:
It began after the stock market crash of October 1929, which sent Wall Street into a panic and wiped out millions of investors. Over the next several years, consumer spending and investment dropped, causing steep declines in industrial output and employment as failing companies laid off workers
Answer:
A and E are the correct.
Explanation:
Examples of the structures that determine function:
a) <u>Chloroplasts </u>only found in plant cells. They work to fix the CO2 in the presence of <u>light energy</u> (sunlight) and convert the reactants into <u>sugar molecules (carbohydrates</u>) that can be used by cells for metabolic functioning.
e) <u>Sperm</u> is the male reproductive cell. Motile sperm cells have a tail-like structure that typically <u>move via flagella</u> and requires a water medium in order to swim toward the egg <u>for fertilization</u>.
Other options are not correct because <u>they don't explain their function according to their structure</u>.
