Which statement best explains why it can be difficult to identify a problem?

a problem can be simple or complicated.
a problem can be personal or emotional.
a problem can be large or small.
a problem can affect people or places.

It can be difficult to identify a problem because a problem can be personal or emotional.
Not every person experiences and sees the things and events the same way. Some event may cause problem to some person, and some not. This problems are personal and emotional, and can be difficult identified because they are subjective. 
Objective problems are easier to identify. 

Mantle convection is the process that drives plate tectonics. the theory of plate tectonics states that the crust is divided into plates that float on the semi molten mantle below. the circular motion of the magma as it slowly rises and falls or move though convection cells drags the plates along causing them to move. the heat source in the lamp would represent the earth's core. the core is the source of energy that drives convection in the mantle. the lava represents molten magma under the earth's surface. if the lava lamp had floating pieces they would move as the circular motion of the lava in the lamp as it rises and falls would move them along the surface. these floating pieces would represent pieces of the earth's crust. 

The answer for your problem would be a. 7