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-BARSIC- [3]
3 years ago
7

The current knowledge concerning cells is the result of the investigations and observations of many scientists. The work of thes

e scientists forms a well-accepted body of knowledge about cells. This body of knowledge is an example of a:________.
a) hypothesis
b) controlled experiment
c) theory
d) research plan
Biology
1 answer:
Dimas [21]3 years ago
3 0

Answer:

This body of knowledge is an example of a theory.

Explanation:

The scientific theory is a conceptual framework used to explain facts or phenomena and to make predictions.

The theory is fundamental to science because it allows scientists to organize and understand observations.

The construction of a theory begins with a hypothesis. The scientist believes that a certain phenomenon occurs in a certain way and so he/she performs observations under the scientific method to prove that his/her hypothesis is valid or not valid. The systematization of the observations as well as of the empirical data collected might derive in a scientific theory that can explain the analyzed phenomenon.

A scientific theory is a knowledge that was contrasted in several ways.

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The Offspring produced by a cross between two given types of plants can be any of the three genotypes denoted by A, B, and C. A
ratelena [41]

Complete question:

The offspring produced between two given types of plants can be any of the three genotypes, denoted by A, B and C. A theoretical model of gene inheritance suggests that the offspring of types A, B and C should be in a 1:2:1 ratio (meaning 25% A, 50% B, and 25% C). For experimental verification, 100 plants are bred by crossing the two given types. Their genetic classifications are recorded in the table below.

<em><u>Genotype       Observed frequency</u></em>

    A             →        18 individuals

    B             →        55 individuals

    C             →        27 individuals

Do these contradict the genetic model?  

Use a 0.05 level of significance.

Determine the chi-square test statistic.

Answer:

Do these contradict the genetic model? No, according to the chi-square test, there is not enough evidence to reject the null hypothesis of the population being in equilibrium.  

Explanation:

<u>Available data</u>:

  • Crossed genotypes: two
  • Genotypes among the offspring; Three → A, B, and C
  • Expected phenotypic ratio → 1:2:1
  • Total number of individuals, N = 100
  • A = 18 individuals
  • B = 55 individuals
  • C = 27 individuals

So, let us first state the hypothesis:

  • H₀= the population is equilibrium for this locus → F(A) = 25%,  F(B) = 50%, F(C) = 25%  
  • H₁ = the population is not in equilibrium

Now, let us calculate the number of expected individuals, according to their expected ratio.

4 -------------- 100% -------------100 individuals

1 ---------------  25% -------------X = 25 individuals A

2 --------------  50% -------------X = 50 individuals B

1----------------- 25%--------------X = 25 individuals C

<u>                                                   A                             B                           C</u>

  • Observed                         18                            55                         27
  • Expected                         25                           50                         25
  • (Obs-Exp)²/Exp                1.96                        0.5                        0.16

<u>(Obs-Exp)²/Exp</u>

A)  (18 - 25)²/25 = 49/25 = 1.96

B)  (55 - 50)² / 50 = 25/50 = 0.5

C)  (27 - 25)²/25 = 4/25 = 0.16

Chi square = X² = Σ(Obs-Exp)²/Exp  

  • ∑ is the sum of the terms
  • O are the Observed individuals: 2 in chamber B, and 18 in chamber A.  
  • E are the Expected individuals: 10 in each chamber  

X² = ∑ ((O-E)²/E) = 1.96 + 0.5 + 0.16 = 2.62

Freedom degrees = 2

Significance level, 5% = 0.05  

Table value/Critical value = 5.99

X² < Critical value

2.62 < 5.99    

<em>These results suggest that there is </em><u><em>not enough evidence to reject</em></u><em> the null hypothesis. We can assume that </em><u><em>the locus under study in this population is in equilibrium H-W.  </em></u>

 

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Rudik [331]

Answer:

All the given statements are correct except b.

Antimicrobial resistance (AMR) refers to the ability of a microorganism to grow in the presence of drug or a chemical that would normally limit its growth or kill it.

It makes it difficult for the existing drugs to eliminate the infection as they become less effective against the microbe.

There are five major mechanisms by which a microbe attains resistance against antimicrobial chemical or drug:

  1. Drug modification or inactivation: A microbial enzyme inactivates the antimicrobial agent. For example, few bacteria produce β-lactamases which provide multi-resistance against β-lactam antibiotics such as penicillin, cephalosporin etc.
  2. Alteration or modification of target site: An altered target site prevents the antimicrobial agent from binding to its target. For example, alteration of penicillin binding protein (PBP) in Methicillin-resistant <em>Staphylococcus aureus </em>(MRSA).
  3. Alteration of metabolic pathway: The microbe uses an alternative pathway to circumvent the blocked pathway. For example, sulfonamides-resistant bacteria started using preformed folic acid in place of  para-aminobenzoic acid (PABA).
  4. Decreased drug accumulation: Microbial efflux pumps remove the antimicrobial agent (before it could do any damage) by pumping it out of the cell.
  5. Decrease in cell permeability: The permeability of the microbial envelope to the antimicrobial agent is decreased
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Which of the following is NOT a limiting factor for coyotes?
olasank [31]

Answer:

D. Thr availability of safe places to rest

Explanation:

Thats like saying people could die because they don't have a place to sleep

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Scorpion4ik [409]
<span>Adaptation is a change or the process of change by which an organism or species becomes better suited to its environment. Knowing the definition of each of the terms is the easiest way to get the answer. </span>
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3 years ago
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