The galaxies aren't distributed randomly throughout the universe but they are grouped in gravitationally bound clusters.
Explanation:
Given that,
Magnitude of vector A, |A| = 15
Magnitude of vector B, |B| = 25
We need to find the magnitude of this sum.
The maximum sum of the resultant vector,

The minimum sum of the resultant vector,

So, the magnitude of this sum either 45 or -10.
Can you further elaborate this isn't making much sense my mans
Explanation:
spectral lines or signatures of elements depend on temperature, the temperature of the sun is about 5800 K.
at this temperature most calcium atoms are excited to higher energy states than hydrogen atoms and this means that calcium atoms are gonna have more signatures than the atoms of hydrogen.
the statement that the sun shows weak hyrogen lines and strong calcium line is wrong because at the sun's temperature most of the hydrogen atoms are in lower energy states while calcium atoms are in higher energy states hence calcium has more or ''strong'' lines than hydrogen.