Answer:
Did alleles for drug resistance occur in bacterial populations that afflict humans, prior to the widespread use of antibiotics in medicine and agriculture? a. No—mutations for drug resistance occur in response to antibiotic use. ... Yes—alleles for resistance arise due to random mutation, so are always present.
Explanation:
Modeling of weathering and erosion can be performed in lab.
<h3>
Procedure of Modeling Weathering and Erosion using graham cracker:</h3>
1. Fill the ice cube tray or other tiny containers with 100 drops of water in each of the two or three cells using the eyedropper. Make the water entirely solid by freezing it for however long(for 3-4 hrs.).
2. Insert one graham cracker section into the bowl. To create a ramp-like structure out of the Graham Cracker, place one end on the bowl's lip and the other end at the bottom. To secure the cracker to the side of the bowl, dab some icing on the back of the cracker.
3.Add water to the eyedropper. Hold the dropper at a height of about 1 inch above the cracker's top. the dropper over the cracker in the middle. Apply 100 drips, always aiming for the same area.
4.Keep an eye on what the cracker does. Keep a record of your findings.
5. Pour the water into a glass that is clear after removing the Graham cracker. Make notes about the water, grading its cloudiness among your observations.
6.In the same manner as in step 2, clean and dry the bowl and add a Graham cracker to it. Grab an ice cube and wipe it over the graham cracker until it melts completely.
7.Remove the graham cracker and pour the melted water into the clear glass.
<h3>Result:</h3>
Appearance of water collected after is moved across graham cracker.
Learn more about weathering and erosion here:
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Answer and Explanation :
Plants and algae comprise the lowest level of the trophic system. Called primary producers or autotrophs, plants and other organisms create their own food using photosynthesis.
Furthermore Each organism in an ecosystem occupies a specific trophic level or position in the food chain or web. Producers, who make their own food using photosynthesis or chemo-synthesis, make up the bottom of the trophic pyramid
They are good because they begin the process of primary succession after a natural disaster.
