If an animal has a set of organs held together and protected by surrounding fluid, the animal is a

The answer is coelomate.

Coelomates are animals which body cavity (coelom) is filled with fluid. Fluid surrounds organs, protects them and allows their free movement and growth. All vertebrates are coelomates.

Pseudocoelomates have pseudocoelom partly filled with fluid. So, fluid surrounds organs, but not as tightly as in coelomates. The example for pseudocoelomates is a roundworm.
Acoelomates have no coelom. The example is a flatworm.

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.