Assertion–Reason (Why do icebergs float?)\nAssertion (A): Icebergs, a solid form of water, float on seawater.\nReason (R1): About two-thirds of an iceberg is below water and one-third above the surface.\nReason (R2): Icebergs are heavier than water and displace seawater, which makes them float.\nDecide which reason(s) truly explain A.

Introduction / Context:
Floating is governed by relative density and buoyancy, not by post-hoc descriptions of how much is submerged. This question probes correct physical reasoning.

Given Data / Assumptions:

• A: Icebergs float.
• R1: About two-thirds submerged and one-third above (a description/observation, not a cause).
• R2: “Icebergs are heavier than water” (factually incorrect; ice is less dense than liquid water).

Concept / Approach:
Buoyancy states that an object floats when its average density is less than the fluid’s density. Sea ice/icebergs (density ~0.92 g/cm^3) are less dense than seawater (~1.025 g/cm^3), hence they float. R1 is an effect/ratio of buoyant equilibrium, not the reason. R2 contradicts the density condition for floating.

Step-by-Step Solution:

Verification / Alternative check:
The correct reason would be “Ice is less dense than seawater; buoyant force balances weight at partial submergence.”

Why Other Options Are Wrong:
A/B/C wrongly confer causal status to a description or a false statement.

Common Pitfalls:
Confusing observed proportions (how much shows above water) with the underlying cause (density difference).

Final Answer:
If neither (R1) nor (R2) is the reason for the assertion (A).