Which observation did researchers make in studies on separated twins?

The scientists observed whether the environment in which each twin was raised had an influence on his personality, behavior and temperament.

Explanation:

As we know, twin brothers have many biological and physical characteristics in common, due to all the genetic load they share. However, some scientists believe that genetics also has half the responsibility for the social characteristics of these brothers, such as behavior, temperament and personality. The other half of that responsibility is held by the environment in which these twins were raised. Thus, twins raised in the same environment, will present equal personalities and behaviors.

For this reason, scientists will start several studies with separate twin brothers who were raised in different environments. They wanted to see how changing the environment would cause differences in the brothers' behavior, temperament and personality.

temp rises, and expansion

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.