Statement I: A needle placed carefully on the surface of water may float, whereas a ball of the same material will always sink.Statement II: The buoyancy of an object depends both on the material and shape of the object.

Needle floats due to surface tension there is no role of buoyant force in its floatingBuoyant force = Vσgwhere V = volume of body submerged in liquid          σ = density of liquid.i.e., the buoyancy of an object depends on the shape of the object.