Natural selection is least likely to be the cause of a change in a population's allele frequencies when: a. there is no competition for resources. b. the population has no genetic variation. c. there is ample genetic variation in the population. d. the ecosystem experiences extreme disturbances.

The answer is B, since the population has no genetic variation it will be classified as an artificial selection not a natural selection.

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.