1. Samples of a microbial colony obtained from the natural environment are not pure culture. They are mixed cultures because the environment consists of an array of microorganisms and not one specific organism. A sample obtained from the natural environment such as water or soil may contain several species of microbes that need to be further isolated to obtain a pure culture.
2. Isolation streak plate technique involves the dilution of the sample several folds and then streaking a small amount using a sterile inoculation loop on an agar plate in a zig-zag manner. This is done to obtain a pure culture of bacteria from a mixed population by separating the microprocessor. When the sample is diluted into a small concentration and is streaked onto agar placed, widely spaced, discrete colonies of bacteria can be observed. These isolated colonies can be further cultured to obtain pure cultures by picking and re-streaking them on fresh agar plates.
3. A microbial colony is considered a pure culture because it consists of single species. A single species of bacteria cluster and form an isolated colony on an agar plate which can be further plated on fresh medium.
3-1 - If your agar plate shows discrete uncluttered colonies then you have obtained an isolated colony. The following picture might help you to understand.
3-2. If you subculture isolated microbes into a sterile nutrient broth without any contamination, it will still be considered pure culture because it is single isolated species in a sterile aseptic environment of the nutrient broth.
3.3. A pure culture can become a mixed culture due to contamination. This could be caused by airborne bacteria if your conditions are not aseptic. Contamination is possible if the work area is not clean and sterile or if the glassware is not sterile. The contamination can transform your pure culture into a mixed culture and is hence problematic. So, it is very important to maintain a sterile and aseptic environment, glassware, and instruments.
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The Georgia Constitution also allows special- purpose districts to be created. These are set up by a city or county in order to meet specific needs of the people
Answer:
Crayon.
Explanation:
A crayon is known to be a kind of stick like pencil, but made of called wax, and it is useful for painting.
It is known that that the first crayon which looks like the modern crayon was made in Europe. And it was initially or originally made then out of the mixture of charcoal and oil. But now, the charcoal has since been replaced by various pigment and the oil been replaced by wax. This because the wax provides a better and stronger writing stick and it is easier to work with.
It should be noted, that crayon is used for writing and drawing, and its invention can be dated back to 18th century.
A is the correct answer.
A Democratic President is likely to appoint, well, Democrats!
A modern Republican held Senate might have problems with that.
So, what has been occurring is that nominations are slowed down or held up if there is a party difference between the Senate and the Presidency.
