Asap! 20 ! which of these statements describes a constraint imposed on scientific researchers by the antarctic treaty system? a. the safety of scientists is ensured. b. some activities are banned. c. scientific knowledge is not shared. d. tourist activities are carefully controlled.

B. Some activities are banned, I believe.

The correct answer is B, I hope this helps..

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.