(a.) That may be inflated.

Lastex accommodating adaptable adaptive adjustable airy animated baleen battledore bendable bending bouncy buoyant chewing gum compliant compressible contractile convalescent dilatant distensive ductile ebullient effervescent elastomer expandable expansible expansile expansional expansive extensible extensile extensional extensive fabricable facile fictile flexible flexile flexuous formable formative gay giving gum gum elastic handball high-spirited impressible impressionable inflatable inflationary jumping jack like putty limber lissome lithe lithesome lively malleable mettlesome moldable plastic pliable pliant racket receptive recuperative recuperatory resilient responsive reviviscent rubber rubber ball rubber band rubberlike rubbery sensitive sequacious shapable soaring spandex spirited sprightly spring springboard springy stretch stretch fabric stretchable stretchy submissive supple susceptible tractable tractile trampoline vivacious volatile whalebone whippy willowy yielding