There are several ways selection can affect population variation:
stabilizing selection
directional selection
diversifying selection
frequency-dependent selection
sexual selection
As natural selection influences the allele frequencies in a population, individuals can either become more or less genetically similar and the phenotypes displayed can become more similar or more disparate. In the end, natural selection cannot produce perfect organisms from scratch, it can only generate populations that are better adapted to survive and successfully reproduce in their environments through the aforementioned selections.
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Answer:
When seeking to determine the number of shirts made by employees subjected to noise with and without the use of headphones, the independent variable is the amount of noise.
Explanation:
During an investigation, the independent variable may be subject to change, in order to observe the effect it will have on the dependent variable.
In the case presented, the amount of noise to which employees are exposed represents the independent variable, which is modified by the use of headphones that block all or part of the noise.
The productivity —expressed in the number of shirts made— can be expected to be higher for employees not exposed to noise.
Other options do not apply because:
- <u><em>The number of shirts made by the employee</em></u><em>. Dependent variable
.</em>
- <u><em>The type of music the employees listen to while they work or the amount of training employees need</em></u><em>. These are not the variables studied.</em>
Answer:
Brain structures called the hypothalamus and pituitary gland control the menstrual cycle.
Explanation:
Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core