DNA is composed of nucleotides, which are composed of three parts:
1. A five carbon carbohydrate (pentose)
Pentose is classified as a monosaccharide (simple carbohydrate), and its molecular formula is represented by 
. They are water soluble molecules with sweet taste. Monosaccharides may have from three carbon atoms (trioses) to six (hexoses). In DNA is present pentose (5 carbon atoms)
2. A nitrogenous base
Nitrogenous bases are ring-shaped compounds that contain nitrogen in their molecular structure. They are classified into two groups: purines and pyrimidines
The purine bases are adenine (A) and guanine (G). They are larger and contain more than one ring in their structure,.
The pyrimidines, cytosine (C), uracil (U) and thymine (T), are smaller and composed of a single ring.
3. One or more phosphate groups
A phosphate consists of a trivalent anion that contains one phosphorus atom and four oxygen atoms. Its molecular formula is expressed by 
.
History of Boston is described below.
Explanation:
- When workers cut down Copp's hill the only thing they left untouched was the old three-acre burying ground. The city built a retaining wall around the graveyard to prevent it from eroding. In 1814, the Boston and Roxbury Mill Corporation built the Boston & Roxbury Mill Dam across the back bay
- Originally called Tremontaine for the three hills in the area, the Puritans later changed the settlement's name to Boston, after the town in Lincolnshire, England, from which many Puritans originated.
- South Boston, which was front and center in the battle, is no longer that close-knit old school “tough-as-nail” Irish Catholic enclave. “Southie,” as it is still fondly referred to, houses the world today flaunting some of the best restaurants and expensive housing in the city
- Boston was founded in 1630 by English Puritans fleeing religious persecution. On 29 March 1630 a fleet of 11 ships carrying 700 people sailed from England to Massachusetts. They were led by John Winthrop (1588-1649). At first the people settled at Charlestown, which had been founded the year before.
- Much of Boston's coastline is man-made land. The original shoreline, from 1630, is visible in dark green on this map. Land made between 1630 and 1995 is light green.Boston is a safe city, but as with any major city, you should take the usual safety precautions. Stay in well-populated areas, travel with others, especially at night, and keep track of your belongings. The tourist areas in Boston are generally safe, but some areas deserve mention.
The virus becoms infection, and they create an epidemic that will last for a long time. This was the case back in the early days.
The answer is <span>prokaryotic cell</span>
Answer:
Two terms might apply for this situation: "<u>jump dispersion</u>" and "human-assisted invasions".
Explanation:
- Dispersion: It refers to the <em>change in an organism's range or distribution area</em>. Different ecological and biogeographical processes might be involved in organisms' dispersion. The term "<u>jump dispersion</u>" refers to a <em>few individuals in a short time that can cross a barrier and occupy a new area</em>. In this situation, the establishment is not always for sure. For this to happen, they must reproduce and start a new population of a certain size that can survive to the new conditions.
- Biologic Invasions: It refers to <em>new species that establish in a new area far or out of their original distribution range</em>. Once established, these species might be <em>considered exotic or invasive, according to their reproductive rate, population growth, and interaction with native species</em>. Biologic invasions are <u><em>natural processes</em></u>, that occur in small groups of individuals that can expand to other ecosystems, and the appearing or despairing of barriers promotes their expansion. <em>But these biologic invasions have accelerated by human beings</em>, referring to this as "<u>human-assisted invasions</u>". These are the cases in which <em>men transport species from one place to the other for different uses or purposes.</em>
It is <em>very common</em> for these species to <em>scape and start new populations</em> in the <em>new area</em>, where they <em>have </em><em>less environmental pressure</em> -fewer predators, more resources, better nitches- than in their origin area, which <em>favors their establishment</em>.
The exposed situation in the example is a case of "human-assisted invasions". It might also be considered as jump dispersion (because a few individuals of the species crossed a barrier and established in a new area) but assisted by humans.
