In insects, what is the adaptive significance of spiracles? in insects, what is the adaptive significance of spiracles? they dilate and constrict during flight or other types of movement, functioning as a "breathing" mechanism. they close off tracheae to minimize water loss. they are thin and highly branched, offering a large surface area for gas exchange. they open into the body cavity, allowing direct contact between hemolymph and tissues.

They close off tacheae to minimize water loss.

The answer is atmosphere. there are four spheres of the earth: 1. geosphere (from greek word 'geo' = ground), 2. hydrosphere (from greek word 'hydro' = water), 3. biosphere (from greek word 'bio' = life), and 4. atmosphere (from greek word 'atmo' = air). a magnetosphere is a region of space around astronomical objects controlled by the magnetic field of that object. through the process of elimination, since lightning is present in the air, it can be found in the atmosphere.