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N76 [4]
2 years ago
14

1. Laura uses a cotton swab to collect microorganisms from a hand rail and streaks a plate. On the fourth day of incubation, she

does not observe visible microbial growth. Given that microorganisms are literally everywhere, give at least three reasons why Laura may not have observed microbial growth?
Biology
1 answer:
weeeeeb [17]2 years ago
3 0

Answer:

The Laura tried to grow micro-organisms in culture broth medium in Petri-plates but the microbial growth was not observed even on the fourth day of culture which could be due to:

1. Laura could have not provided the correct broth medium maintaining the with pH and salt concentrations.

2. Microorganisms did not get optimal growth conditions.

3. The bacterial source could have died after the collection which could have lysed after their death and thus no longer visible.

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In humans, Rh-positive individuals have the Rh antigen on their red blood cells, while Rh-negative individuals do not. If the Rh
Marta_Voda [28]

Answer:

D. 0.60

Explanation:

If the population is in Hardy-Weinberg equilibrium, the genotypic frequencies are:

  • freq AA = p²
  • freq Aa = 2pq
  • freq aa = q²

<em>p</em> is the frequency of the Rh positive allele (A) and <em>q</em> is the frequency of the Rh-negative allele (a).

If 84% of the population is Rh-positive, then 16% is Rh-negative and has the genotype <em>aa</em>. Therefore:

q² = 0.16

q = √0.16

q=0.4

And because p+q=1,

p = 1 - 0.4

p = 0.6

The frequency of the Rh-positive allele is 0.6

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Why must nations sometimes work together to solve environmental problems
Black_prince [1.1K]
Because some problems are not always small enough for one nation that can do it by themselves and need more helpo
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Predict how the sympathetic reflexes controlling blood vessels would respond to a sudden decrease in blood pressure
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<span>Baroreceptors are special receptors that detect changes in your blood pressure. Important baroreceptors are found in the aorta and the carotid sinus. If the blood pressure within the aorta or carotid sinus increases, the walls of the arteries stretch and stimulate increased activity within the baroreceptors.</span>
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Sex linked traits are more common in _________.<br><br> males<br><br> females
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Males is the answer

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If the ancestral form for a particular lineage was aquatic and used gills for respiration, what changes would you expect to see
Marat540 [252]
<h2>The Respiration of Gills</h2>

Explanation:

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