A flight simulator that helps astronauts prepare for a shuttle launch is an example of a Scientific Model.
External fertilization in animals usually occurs in water or in damp areas in a process called spawning.
The answer is D) 144 grams O2
1 significant figure, because there is no decimal after the zero the zero doesn't count.
The answer is 7. Valence electrons are the electrons in the very last shell, so we need to look at the outer “circle” and count the electrons, or the little black dots. There are 7 in the last shell.