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.
<span>Only a single amino acid could change, because the reading frame is unaffected</span>
Given that,
The speed of a wave, v = 200 m/s
Wavelength, 
We need to find the frequency of this wave. The relation between wavelength, frequency and the speed is given by :
So, the frequency of this wave is 100 Hz.
To reduce the likelihood of human error, to gather more evidence, and to make his numbers more exact.
Orbits are the result of a perfect balance between the forward motion of a body in space, such as a planet or moon, and the pull of gravity on it from another body in space, such as a large planet or star. ... These forces of inertia and gravity have to be perfectly balanced for an orbit to happen.
