Bacteria are classified into 5 groups according to their basic shapes: spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochaetes). They can exist as single cells, in pairs, chains or clusters.
Answer is b. Thiamine
Vitamins are essential nutrients which are crucial for maintaining optimal health. Vitamin B-complex is a water soluble vitamins which includes thiamine (B1), niacin (B3) riboflavin (B2), folate and iron. These are added during enrichment process of foods like cereal grains and breads, as well as other foods such as meat, poultry, eggs, fish milk, legumes, etc.
<h2>Neural crest </h2>
Explanation:
The neural crest likely forms: neurons and glia of the peripheral nervous system
- The neural crest are bilaterally paired strips of cells arising in the ectoderm at the margins of the neural tube
- In the body region, neural crest cells also contribute the peripheral nervous system (both neurons and glia) consisting of sensory ganglia (dorsal root ganglia), sympathetic and parasympathetic ganglia and neural plexuses within specific tissues/organs
- The nervous system is made up of specialized cells which includes nerve cells (or neurons) and glial cells (or glia)
- Neurons are the basic functional units of the nervous system, and they generate electrical signals called action potentials, which allow them to quickly transmit information over long distances
- Glia are also essential to nervous system function, but they work mostly by supporting the neurons
Answer:
The next generation average time to flowering will be 98 days.
Explanation:
Before answering the question, we need to know a few concepts.
- Artificial selection is the selecting practice of a specific group of organisms in a population -that carry the traits of interest- to be the parents of the following generations.
- Parental individuals carrying phenotypic values of interest are selected from the whole population. These parents interbreed, and a new generation is produced.
- The selection differential, SD, is the difference between the mean value of the trait in the population (X₀) and the mean value of the parents, (Xs). So,
SD = Xs - X₀
- Heritability in the narrow-sense, h², is the genetic component measure to which additive genetic variance contributes. The heritability might be used to determine how the population will respond to the selection done, R.
h² = R/SD
- The response to selection (R) refers to the metric value gained or lost from the cross between the selected parents. R can be calculated by multiplying the heritability h², with the selection differential, SD.
R = h²SD
R also equals the difference between the new generation phenotypic value (X₁) and the original population phenotypic value (X₀),
R = X₀ - X₁
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Now that we know these concepts and how to calculate them, we can solve the proposed problem.
<u>Available data: </u>
- trying to decrease the maturation time in a population of sunflowers.
- the population mean time to flower is 100 days → X₀
- Chosen parental Plants mean flowering time is 90 days → Xs
- the narrow-sense heritability for flowering time is 0.2 → h²
According to what we sow previously, we need to find out the value of X₁, which reflects the next generation average time to flowering.
- We know that R = X₁ - X₀, so we need to clear this formula to calculate X₁
X₁ = R + X₀
We already know that X₀ = 100 days,
Now we need to calculate R.
We know that h² = 0.2,
Now we need to calculate SD
Xs = 90 days → Parentals media flowering time
X₀ = 100 → Population media flowering time
SD = Xs - X₀
SD = 90 - 100
SD = - 10 days
Knowing this, we can calculate R
o h² = 0.2
o SD = - 10
R = 0.2 x (-10)
R = - 2
- Finally, once we know the R-value we can calculate the X₁ value
X₁ = R + X₀
X₁ = - 2 + 100
X₁ = 98
