(a) Ice will have more volume submerged inside water, because density of ice is more than the density of wood and we know that the body with higher density will have more volume submerged in water.
(b) Ice will have more volume submerged inside water and hence it will experience greater upthrust than the piece of wood. This is so because the upthrust is always equal to the volume of water displaced by the submerged part of the body and ice will displace more water than the piece of wood.