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3 years ago

Which of the following represents a testcross

Biology

1 answer:

STatiana [176]3 years ago

5 0

Answer:

The option should be like this:

A- T? x tt

Explanation:

In an inheritance pattern in which a particular allele is exhibiting doiminance over the other, the dominant phenotype can either be homozygous or heterozygous. Hence, it is impossible to tell the genotype of a dominant phenotype by merely observing it. A cross called TEST CROSS is used.

A test cross is a cross used to determine the actual genotype of a dominant phenotype i.e. whether it is homozygous or heterozygous by crossing tye unknown genotype with a homozygous recessive parent. If all of the offspring of this cross have a dominant phenotype, it means the dominant parent is HOMOZOGOUS but if offsprings with an equal ratio of dominant and recessive phenotypes are produced, it means the dominant parent is HETEROZYGOUS.

In this case, the dominant phenotype whose genotype is unknown is (T*) while the recessive parent will be (tt).

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List two additional populations (other than those listed in the lab) for which

omeli [17]

Indirect methods like mark and recapture become a strong tool to estimate population size or density in species on which it is impossible to apply a direct methods. Because of their biological and ecological characteristics, the Gypsy moth and the Green lizard populations are good examples for which mark and recapture would work well.

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There are different methods to study population density. There are direct methods and indirect methods. Among these last ones, we might find the Mark-Recapture technique.

The Mark-Recapture technique assumes that

the population is closed during the sampling season, there is no mortality nor natality,
marks in the individual last the whole sampling season, and they do not affect the marked individual or their behavior.
marked individuals are randomly distributed in the population, and
all the individuals have the same probability of being sampled.

The method consists of capturing a sample of individuals belonging to the population under study. After capturing the individuals, the researcher marks and releases them again. The third step is to sample again: The researcher captures new individuals and counts how many of them are marked. These marked individuals belong to the first sample.

Indirect methods like this become a strong tool to estimate population size or density in species on which it is impossible to apply a direct method such as counting individuals.

For instance, if we need to estimate insects population density (Gypsy moth population) or reptiles population density (Green lizard population) because of their biological and ecological characteristics, the best way of doing it is by applying indirect methods. These species characterize as small-sized, fast to escape, they can hide in small inaccessible places, they have nocturnal habits, their reproductive rate is too high, and their distribution rate is wide. Among many other characteristics, their population density can not be estimated by direct methods. Mark-Recapture technique is the most suitable one.

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6 0

3 years ago

Which role do ultrafine particles play in dirty air?

topjm [15]

Answer:

They can worsen symptoms for people with breathing difficulties.

Explanation:

Ultrafine particles are small particles found in dirty air. They aren’t filtered due to their very small size. They enter the lungs and cause certain conditions such as oxidative stress, inflammatory mediator release, and could induce heart disease, lung disease and other systemic effects.

People who have breathing difficulties have their case worsened due to these particles.

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4 years ago

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Alex787 [66]

Answer:

1- The polar section of a phospholipid is the part with the phosphate group. This is sometimes called the polar head of the molecule.

2- The phosphate group is the negatively-charged polar head, which is hydrophilic. The fatty acid chains are the uncharged, nonpolar tails, which are hydrophobic.

Explanation:

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3 years ago

Which is the central element for all living things?

Tatiana [17]

The central element for all living things is carbon, which is why you might often hear the phrase "carbon-based" lifeforms. Another term is often "organic matter"

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4 years ago

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Imagine a patient came into your medical practice. What are symptoms that, collectively, would indicate a possible respiratory p

o-na [289]

Answer: 1. Cancer 2. Blood virus 3. heart problems

Explanation:

hope this helps

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3 years ago