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3 years ago

Compare and contrast the TWO classes of "seeded "plants.

Biology

1 answer:

atroni [7]3 years ago

7 0

Answer:

The seed plants are often divided arbitrarily into two groups: the gymnosperms and the angiosperms. The basis for this distinction is that angiosperms produce flowers, while the gymnosperms do not.

Explanation:

The seed plants are often divided arbitrarily into two groups: the gymnosperms and the angiosperms. The basis for this distinction is that angiosperms produce flowers, while the gymnosperms do not. This is poor form, since it defines the gymnosperms by the absence of a character, and not by any features that the organisms actually share. The gymnosperms do share a number of features, but, as should be obvious from the above cladogram, they are not more closely related to each other than to the angiosperms (Anthophyta). The features shared by gymnosperms were likely present in the early ancestors of the flowering plants as well. It should also be noted that the "progymnosperms" are represented by a box of a different color, in order to make it clear that they are not actually seed plants, but rather are included here because they are believed to be the closest relatives of the seed plants.

Systematics within the seed plants is poorly understood. Part of the problem is that most of the major groups have gone extinct, and several of the groups alive today consist primarily of plants with highly derived morphologies. The above cladogram is based largely on the work of Jim Doyle, a professor at UC Davis, and Michael Donoghue, currently at Harvard, and is therefore somewhat preliminary. It includes some questionable groupings not explicitly supported in their papers.

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Sati [7]

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3 years ago

What are the parts of animal and find their function.

REY [17]

Answer:

<h2>⚪parts of animals are:</h2>

tail,claws,wings, beak ,fur , fins, she'll, feather.

<h2>⚪function of animal parts</h2>

Many land animals use their tails to brush away flies and other biting insects. Some species, including cats and kangaroos, use their tails for balance; and some, such as monkeys and opossums, have what are known as prehensile tails, which are adapted to allow them to grasp tree branches.

<h3>claws:</h3>

Claws may be adapted for scratching, clutching, digging, or climbing. By analogy, the appendages of other lower animals are frequently called claws. The claw's shape is ordinarily suited to the food-getting habit of the animal.

Wing, in zoology, one of the paired structures by means of which certain animals propel themselves in the air. ... The primary flight feathers on the distal portion of the wing create most of the propelling force in flight, while on the less mobile upper wing the secondaries provide the greater portion of the lift.

All birds have one beak. But it has evolved differently in each species to improve its functions in response to its environment. These functions include feeding themselves and their young, defending themselves, grooming their feathers, mating, regulating their body temperature or building nests.

Fur is a thick growth of hair that covers the skin of many different animals, particularly mammals. ... The fur of mammals has many uses: protection, sensory purposes, waterproofing, and camouflaging, with the primary usage being thermoregulation.

Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. ... Fish, and other aquatic animals such as cetaceans, actively propel and steer themselves with pectoral and tail fins

<h3>shell:</h3>

Turtles and tortoises are some of the best-known shell-dwelling creatures. The difference between them is that tortoises live on land while turtles prefer the water

<h3>feather:</h3>

Feather Function: What do feathers do? Each feather on a bird's body is a finely tuned structure that serves an important role in the bird's activities. Feathers allow birds to fly, but they also help them show off, blend in, stay warm, and keep dry.

Explanation:

<h2>hope it helps you</h2><h2>please mark me brainliest</h2>

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3 years ago

Describe the size and scale of an atom. Explain the relative size of the nucleus in relation to the size of the entire atom.

arlik [135]

The size of the nucleus of an atom is about 10 raise to power 15 meter, which basically proposes that it is about 10 raise to power -5 or 1/100,000 we can say of the size of the entire atom. A good comparison of the nucleus to the atom is just like a pea in the midst of a track. The volume of the atom is 2 x 1013 times larger than its nucleus.

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4 years ago

How microorganism can be identify as etiological agent of an infectious disease

N76 [4]

Answer:

Only when a microorganism has successfully established a site of infection in the host does disease occur, and little damage will be caused unless the agent is able to spread from the original site of infection or can secrete toxins that can spread to other parts of the body. Extracellular pathogens spread by direct extension of the focus of infection through the lymphatics or the bloodstream. Usually, spread by the bloodstream occurs only after the lymphatic system has been overwhelmed by the burden of infectious agent. Obligate intracellular pathogens must spread from cell to cell; they do so either by direct transmission from one cell to the next or by release into the extracellular fluid and reinfection of both adjacent and distant cells. Many common food poisoning organisms cause pathology without spreading into the tissues. They establish a site of infection on the epithelial surface in the lumen of the gut and cause no direct pathology themselves, but they secrete toxins that cause damage either in situ or after crossing the epithelial barrier and entering the circulation.

Most infectious agents show a significant degree of host specificity, causing disease only in one or a few related species. What determines host specificity for every agent is not known, but the requirement for attachment to a particular cell-surface molecule is one critical factor. As other interactions with host cells are also commonly needed to support replication, most pathogens have a limited host range. The molecular mechanisms of host specificity comprise an area of research known as molecular pathogenesis, which falls outside the scope of this book.

While most microorganisms are repelled by innate host defenses, an initial infection, once established, generally leads to perceptible disease followed by an effective host adaptive immune response. This is initiated in the local lymphoid tissue, in response to antigens presented by dendritic cells activated during the course of the innate immune response (Fig. 10.2, third and fourth panels). Antigen-specific effector T cells and antibody-secreting B cells are generated by clonal expansion and differentiation over the course of several days, during which time the induced responses of innate immunity continue to function. Eventually, antigen-specific T cells and then antibodies are released into the blood and recruited to the site of infection (Fig. 10.2, last panel). A cure involves the clearance of extracellular infectious particles by antibodies and the clearance of intracellular residues of infection through the actions of effector T cells.

Explanation:

if wrong correct me

4 0

3 years ago

Ellis-van Creveld syndrome is a recessive genetic disorder that includes the characteristics of short stature and extra fingers

e-lub [12.9K]

Answer:

D. The frequency of the Ellis-van Creveld allele is 0.0447 in the isolated population and 0.0026 in the general population, which suggests that genetic drift has occurred in the isolated population.

Explanation:

If we assume that one gene is involved in Ellis-van Creveld syndrome and we name that gene with A, then the genotype of the syndrome would be aa.

In population 1, the frequency of the syndrome is 1/150000=0.0000066(it is the frequency of the aa gentotype)

In population 2, the frequency of the syndrome is 1/500=0.002

According to Hardy-Weinberg equilibrium

p2+2pq+q2=1 (p2 is the frequency of the dominant homozygous, 2pq is the frequency of heterozygous and q2 is the frequency of the recessive homozygous).

q or the frequency of the Ellis-van Creveld allele in Population 1 is $\sqrt{0.0000066}$ =0.0026

q or the frequency of the Ellis-van Creveld allele in Population 2 is $\sqrt{0.002}$ = 0.0447

6 0

4 years ago

Compare and contrast the TWO classes of "seeded "plants.​

Compare and contrast the TWO classes of "seeded "plants.