D. A plateau period means that there is no change, bad or good. Options A-C are exciting changes, meaning there is an uphill change. However in D, nothing is changing at all.
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.
Learn more about subcultured at
brainly.com/question/26525141
#SPJ4
Answer: The correct sequence of steps in a research process is Selection/Identification of the problem, Review of Literature, Collect Data and Analyse the Data.
Explanation: The detailed sequence of steps in a research process involves;
Step 1: Identify the Problem.
Step 2: Review the Literature.
Step 3: Clarify the Problem.
Step 4: Define Terms and Concepts.
Step 5: Define the Population.
Step 6: Develop the Instrumentation Plan.
Step 7: Collect Data.
Step 8: Analyze the Data.
The Marshall Plan, also known as the European Recovery Program, was a U.S. program providing aid to Western Europe following the devastation of World War II. It was enacted in 1948 and provided more than $15 billion to help finance rebuilding efforts on the continent. The brainchild of U.S. Secretary of State George C.
Answer:
--helps bind people together by creating bonds of mutual obligation.
---is only appropriate when people do not expect anything in return for their gift.
Explanation:
Reciprocity is the act of giving a person a gift without expecting something in return. Generalized reciprocity creates a moral obligations among the people in the society. This is usually practiced among common friends and people who are closely attached to one another.
When there is a reciprocity, a smile or love or kindness or thank you is always included in the exchange. It binds the people together and bring them close top each other in the society by binding them with mutual obligations.
