What is the relationship between ka and kb with kw?
the sum of ka and kb equals the auto-dissociation constant for water. the product of ka and kb equals the auto-dissociation constant for water. the quotient of ka and kb equals the auto-dissociation constant for water. the difference of ka and kb equals the auto-dissociation constant for water.

Answer is: The product of Ka and Kb equals the auto-dissociation constant for water.

Reaction of  auto-dissociation for water: H₂O ⇄ H⁺ + OH⁻.

Water dissociates (autoionization) to form hydrogen ions (H⁺) and hydroxide (OH⁻) ions. The protons (H⁺) hydrate as hydroxonium ions( H₃O⁺).

The Kw (the ionic product for water) at 25°C is 1·10⁻¹⁴ mol²/dm⁶ or 1·10⁻¹⁴ M². Concentration of hydrogen ions and hydroxide ions in pure water are the same.

Ka · Kb = Kw;  the ionic product of water.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.