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antoniya [11.8K]
3 years ago
6

Residents of three villages with three different sources of water supply were asked to participate in a survey to identify chole

ra carriers. Becuase several cholera deaths had occurred lately, nearly everyone agreed to be examined. The proportion of residents in each village who were carriers was computed and compared. What kind of study was this?a. Cross-sectional study
b. Case-control study
c. Prospective cohort study
d. Retrospective cohort study
e. Experimental study
Biology
1 answer:
lubasha [3.4K]3 years ago
3 0

Answer:

<em>a. Cross-sectional study</em>

Explanation:

A cross-sectional analysis <em>includes at one particular point in time looking at data from a population.</em> Participants are chosen based on specific variables of interest in this type of study.

For developmental psychology, cross-sectional experiments are often used, but this approach is also used in many other fields, including social science and education.

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AleksandrR [38]

Answer:

  1. RNA polymerase is always present in the cell, but sometimes present in viruses.
  2. tRNA is always present in the cell but never present in viruses.
  3. Ribosomes are always present in a cell but never present in viruses.
  4. Genes are always present in the cell, but always present in viruses.

Explanation:

  • Viruses are acellular microorganisms that do not have a biochemical or gene expression of their own. They hijack the host's gene expression system.
  • RNA polymerase is the enzymes that forms RNA primers during DNA replication and the mRNA transcript of template DNA during transcription. Therefore, RNA polymerase is always required in cells.
  • Most viruses lack RNA polymerase except some RNA viruses such as polio viruses that contain an RNA dependent RNA polymerase, an enzyme that synthesizes mRNA from an RNA template.
  • Viruses lack tRNA and ribosomes as they are not capable of translation on their own.
  • Unlike the gene expression machinery, all organisms including viruses have a genome. Viruses can have both DNA and RNA genomes.

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3 years ago
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sladkih [1.3K]

Answer: These may be:

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Explanation:

Plants employ several methods in order to defend themselves from pathogens. These may be physical defenses or chemical ones. Several have adaptations to their surfaces that prevent the entry of pathogens, called physical barriers such as

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Chemical defenses include the production or secretion of:

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4. How do chromosomes participate in gene transmission? As mentioned above, genes are part of DNA and DNA is the molecule that makes up chromosomes, in this case, chromosomes are molecules loaded with genes. In the human body, cells have 46 pairs of chromosomes, with the exception of gametes that have half that number. During the reproductive process, the gametes (reproductive cells) divide and produce a new being. The mother's gametes unite with the father's gametes to form a new being. Each gamete has 23 chromosomes, which contain the genes responsible for transmitting the characteristics.

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