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)
The sun--solar energy--is at the heart of the cycle of life, with all the sustenance relationships referred to as the food web. The sun is the ultimate source of energy for animals, but its energy must be harnessed by plants before it can be used by animals. Animals get energy by processing complex foods.
Answer:
By researching, I would think that the answer is D. Ice crystals melt as they fall through a warm layer of air and then refreeze into small ice pellets as they pass through a colder layer of air.
Explanation:
<em>During precipitation formation, if temperatures are at or below freezing, 0°C (32°F), at cloud level, water in the air freezes into ice crystals, and the crystals stick together to make snow. The snow starts to fall, and if the air column is freezing cold all the way down from the clouds to the ground, the precipitation stays frozen. It simply falls as snow.</em>
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<em>Sometimes, however, a temperature inversion occurs. Normally, the temperature decreases with increasing altitude. A temperature inversion is when a layer of warm air intrudes between the ground and the clouds.</em>
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<em>Under these conditions, when the falling snow reaches the layer of warm air, it melts. Then it hits the layer of cold air just above Earth’s surface and refreezes. This all happens very fast, and the result is tiny ice pellets called sleet.</em>
Answer:
The genotype for the pink flower is Rr and the genotype for the white flower
is rr. This would lead to a 50% chance of the offspring having a phenotype of pink.
Explanation:
