The main reason that marine sediments formin layers is becau

The main reason that marine sediments formin layers is because they

a. Are only laid down intermittently during periods of heavy rain or wind

b. Are formed of different types of material settling all the time

c. Are constantly being formed and reformed by turbidity currents

d. Tend to change consistency and color due to biological activity

Solution

Answer: (d)

The main reason that marine sediments form in layers is because they tend to change consistency and color due to biological activity.

Biogenic (biochemical) sedimentary rocks are those composed of materials formed by the activity of living organisms such as coal (compacted undecayed plant matter) and many limestones which are made up of the shells or other skeletal fragments from marine organisms.