Draw c4h8br2 that has the following 1h nmr spectrum: 1.97 (s, 3h), 3.89 (s, 1h). hint: draw c4h10 (there are two isomers), and then replace two h atoms with br atoms.

answer: they produce more slow than unicellular organisms.

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter  

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.