Answer:
<h2>D. Competitively dominant to other organisms in the ecosystem</h2>
A keystone species is an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether.
<em>Hope that helps! :)</em>
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<em>-Aphrodite</em>
Explanation:
Sugar cane has a lot of iron in it which helps oxygen distribution in the brain.
The EMB (Eosin Methylene Blue) agar is a selective and differential agar medium. It contains sucrose and lactose as fermentable substrates together with Eosin Y and methylene blue dyes which in combination gives the agar its characteristic color when prepared and serves as a pH indicator as well as an inhibitor of growth of Gram-positive bacteria. Hence, it is primarily used to isolate Gram-negative fecal coliforms while some positive fecal coliforms such as Staphylococci are also able to grow.
These coliforms are of two types:
- Lactose or sucrose fermenting coliforms form metallic sheens on the agar as a result of acid production and the response of the indicator to the increased acidity.
- Non-lactose/sucrose fermenters are only able to produce acid by protein deamination. Hence they either form colorless or pinkish colonies on the agar
On the other hand, Mannitol salt agar is a selective and differential agar medium that is primarily used to isolate Staphylococcal bacteria. The presence of sodium chloride in the medium makes it a partial or complete inhibitor of other bacteria.
Hence, an unknown bacterium that forms colorless colonies on EMB will either be a non-lactose fermenting, Gram-negative coliform that will hardly grow on Mannitol salt agar, or a Gram-positive fecal Staphylococcus.
Staphylococci bacteria are of two types:
- Coagulase-positive will form yellow colonies on the Mannitol salt agar.
- Coagulase-negative will form red colonies on the Mannitol salt agar.
More about isolating media can be found here: https://brainly.in/question/7238948
<h2>B) option is correct </h2>
Explanation:
Natural selection is a selection pressure which operates in a population and allow the best fitted genotype to survive in changing environmental conditions and eliminate the other genotype which are not fit
In artificial selection, breeders select superior breed for the breeding purpose so that this type of selection favors the superior genotype and eliminates inferior genotype, thus leading to genetic drift
Stabilizing selection is a type of natural selection in which intermediate genotype is favored but extreme genotypes (inferior and superior) are eliminated
In the given example of pigmentation in pigeons, breeding is selectively done with intermediate pigmentation hence intermediate genotypes will be favored
