The deep scattering layer (DSL): a) was discovered by Charles Darwin
b) is only seen at night
c) is a biological phenomenon that can be detected with sonar
d) is not a biological phenomenon
e) is a chemical boundary in the water

C

Explanation:

Because its a region of high biological productivity with a lot of water organism allowing for high reflectivity of sonar pulse mimicking ocean bottom

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force