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Answer:

a) A whale is a mammal because it possesses certain characteristics that define mammals. These characteristics include giving birth to live young, having mammary glands that produce milk, and having hair or fur on their bodies. Whales, despite their aquatic lifestyle, share these common mammalian traits.

b) Radiation is the fastest way of heat transfer because it involves the transfer of heat energy through electromagnetic waves. Unlike conduction and convection, which require a medium (solid, liquid, or gas) for heat transfer, radiation can occur in a vacuum and does not rely on direct contact between objects. This makes radiation the fastest method for transferring heat energy over long distances.

c) Both liquid classes do not crack on heating because liquids lack a fixed shape and can flow freely. Unlike solids with a definite and organized structure, liquids have a more random arrangement of molecules. This allows them to expand when heated without undergoing a phase change, preventing cracking.

d) Mercury is liquid at room temperature but is a metal because it is an exception to the general rule that metals are solid at room temperature. Mercury remains liquid due to its unique atomic structure and weak metallic bonding forces. It is the only metal that is liquid at standard room temperature.

e) High-tension wires are loosened in winter and tightened in summer to account for temperature-related changes in the materials. In cold temperatures, materials contract, causing the wires to contract and potentially become too tight. In hot temperatures, materials expand, and if the wires were initially tightened, they may become agitated. Adjusting the tension helps prevent damage and ensures the stability and safety of the wires throughout different temperature conditions.

Explanation:

Answer:

a)a whale is a mammal because it directly give birth to the young ones