Answer:
A. plot an H-R diagram for the stars in the cluster.
Explanation:
A star cluster can be defined as a constellation of stars, due to gravitational force, which has the same origin.
The astronomy student would have to plot an H-R diagram for the stars in the cluster and determine the age of the cluster by observing the turn-off point. The turn-off is majorly as a result of gradual depletion of the source of energy of the star. Thus, it projects off the constellation.
Nitrogen fixing bacteria changes dead plants and animals into ammonia compounds.
<h2>What is nitrogen fixation?</h2>
Atmospheric nitrogen is converted into nitrogen oxides by the action of lightning, which helps its incorporation into the soil.
<h3>Characteristics of Nitrogen fixing bacteria</h3>
- Nitrogen is fixed by these bacteria and other prokaryotes through various metabolic processes, which convert it into different usable compounds, such as ammonia (NH3) and ammonium ion (NH4+).
- These microorganisms can be found in soil and water, or as plant symbionts.
Therefore, we can conclude that nitrogen fixing bacteria fix nitrogen from the air, that is, they originate soluble compounds by plants, such as ammonia.
Learn more about nitrogen fixation here: brainly.com/question/14726009
The Electric field is zero at a distance 2.492 cm from the origin.
Let A be point where the charge 
C is placed which is the origin.
Let B be the point where the charge 
C is placed. Given that B is at a distance 1 cm from the origin.
Both the charges are positive. But charge at origin is greater than that of B. So we can conclude that the point on the x-axis where the electric field = 0 is after B on x - axis.
i.e., at distance 'x' from B.
Using Coulomb's law, 
,
= 
k is the Coulomb's law constant.
On substituting the values into the above equation, we get,
Taking square roots on both sides and simplifying and solving for x, we get,
1.67x = 1+x
Therefore, x = 1.492 cm
Hence the electric field is zero at a distance 1+1.492 = 2.492 cm from the origin.
Learn more about Electric fields and Coulomb's Law at brainly.com/question/506926
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