Answer:
d) Chemical composition of its outer regions
Explanation:
Spectroscopy is the study of spectral lines, it's an important part of studying the chemistry that goes on in stars and interstellar clouds, spectral lines can give relevant information because every atom or molecule gives off light at a specific frequency, thus, astronomers can look for gas containing a particular atom or molecule by tuning the telescope to one of the gas's characteristic frequencies. Therefore, we can know the chemical composition or a star's outer regions analyzing the spectral lines.
Even though the spectral shape of a blackbody continuum depends on the temperature of the object an there's a relationship between an object’s temperature and the peak of its spectrum, we don't consider this answer as correct because we are not measuring spectral lines but the continuum.
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Explanation:
1. Oxygen, without oxygen no human can live, In space, there Is zero oxygen
2. Water, Astronauts will definitely need some sort of water since nearly every living thing requires It
<span>Unpredictable floods, small & defenseless region, and limited natural resources.</span>
An object moving in a circle is accelerating, even if it moves with a constant speed because the velocity changes.
<u>Explanation:</u>
The direction of an object changes constantly during its movement in circle at a constant speed. As the direction changes it results in changing the velocity of that object. This happens since velocity has direction and magnitude.as it is vector quantity.
An object will have acceleration only if a resultant force is acting on that body. When an object is moving in a circle, this resultant force is the centripetal force that is acting towards the center of the circle.