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 first civilizations developed in North Africa, Middle East, and South and East Asia because of the advantages that this areas offered to the people inhabiting them. The biggest advantage were the big rivers with long and wide fertile plains beside them, which enabled the people to be involved in agriculture and produce big amounts of food and even reserves. Since the food problem was solved, they were able to concentrate on other things in their spare time and started to develop architecture, sciences, philosophy, writing systems...
Answer:
C, the relationship between Massasoit and New England colonists
Explanation:
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Answer:
Creating social media profiles
Explanation:
Is expected that the users alreday have their own media profiles. Also, creating a profile does not garantee any interaction or engagement with other users, a platforms or a specified segment. The best way sto angage users to any product/media are to share content, angege key influencers, be in touch with the target subjects and broadcast relevant content.
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