Q1: Si particles

ANS:A - show dilatancy

Examples.

Corn starch and water (oobleck)

Cornstarch is a common thickening agent used in cooking. It is also a very good example of a shear thickening system. When a force is applied to a 1:1.25 mixture of water and cornstarch, the cornstarch acts as a solid and resists the force.
Silica and polyethene glycol.

Silica nano-particles are dispersed in a solution of polyethylene glycol. The silica particles provide a high strength material when flocculation occurs. This allows it to be used in applications such as liquid body armor and brake pads.

Quicksand
Quicksand is a natural case of a shear thinning, non-Newtonian fluid. This is the opposite of a dilatant. As its strain rate increases, its resistance to shear will decrease causing the system to act more like a liquid than a solid. Hence, as one thrashes about in quicksand one sinks faster as the mixture's resistance decreases.