Neurotoxin that magnifies within food webs; typically found in polluted bodies of water; it poisoned thousands of people when it was dumped into a Japanese bay; people who ate contaminated fish from the waters exhibited convulsions, slurred speech, loss of muscle control, and sudden fits of laughter; some people died

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.

Very hard to understand

  like australopithecus afarensis; probably the direct ancestor of this group. africa: 5.8 to 4.4 million years ago. 

The first means of speeding up reactions mentioned by the speaker is raising the enzymes