15. What is one way in which scientists study dark matter?
O A They study how light bends around a galaxy or
galaxy cluster.
OB They study shadows that are cast onto a galaxy
or galaxy cluster.
O C They study changes in the number of galaxies in
a galaxy cluster.
OD They study how the brightness within a galaxy or
galaxy cluster changes.

It's d

Explanation:

Scientists study dark matter by looking at how it affects visible matter.

emily ruth's annual premium is $1058.50

step-by-step explanation:

emily ruth is a female of 27 years age purchasing 20 year endowment insurance with face value $25000.

from the given table,

for females, the age of a male 3 years younger should be used.

so, we have to check for 24 year male for 20 year endowment.

it is 42.34 for every $1000 face value.

for a face value of $25000,

it is 25 * 42.34 = $1058.50

∴ emily ruth's annual premium is $1058.50