1. Which kind of evidence did scientists use to determine that some animals moved back to a marine life after first evolving as land mammals? a. The fossil record
b. Comparison of homologous structures
c. DNA evidence
d. All of the above

The answer is d i think

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.