Psychology : why can freud’s conception of consciousness be compared to an iceberg?

In Freud’s conception, consciousness can be broken up into three distinct bands: the conscious level, the preconscious level, and the unconscious level.  The conscious level, where we process our perceptions and thoughts, is like the part of the iceberg that is above the water.  We are aware of our conscious level, just as we are aware of the top layer of an iceberg. The next level of consciousness, the preconscious level, is just below the surface of our consciousness and can be accessed when it is needed to recall memories and facts. This is similar to the level of the iceberg directly under the water: you can perceive it if you look carefully and are close enough. The last level of consciousness is the unconscious level, which a person has no active knowledge of.  Like the vast underwater portion of an iceberg, the unconscious level is unseen but can be very influential.  The unconscious mind has many urges, instincts, and desires, which it is constantly demanding be met. The unconscious mind can influence the behavior of an individual, sometimes in the disastrous ways an iceberg can threaten a ship.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).

1.195000

explanation:

total mass=0.0117+0.0137+0.0881+0.0111

total mass= 0.01172kg

total velocity = 0.283-0.743+0.871-0.799+0.155+0.637+0.301=0.102

momentum=mv=0.1172*0.102=1.195000//