Q1. Some metals sink in water because:
A their density is more than that of water. Correct
B their density is less than that of water.
C their surface area is less than that of water.
D their mass is more than that of water.
Explanation
An object sinks in water when its density is greater than the density of water, so metals such as iron sink. If a substance has lower density than water, it tends to float, as wood or oil may do. Surface area can affect how an object rests on water for a short time, but it is not the basic condition for sinking. Mass alone is also not enough: a heavy ship can float because its average density is kept lower than water by its shape and trapped air.