Question

So-called "dark matter" cannot be directly observed because

A it makes up less than one-tenth of the total mass of the universe
B it gives off no radiation
C it moves too quickly to be captured in space telescope images

Answer 1

B

Step-by-step explanation:

it gives off no radiation

Answer 2

B. it gives off no radiation

Step-by-step explanation:

Dark matter is so named because it neither absorbs nor emits light and therefore cannot be directly observed.