When you can not see what is taking place, but other senses indicate occurences. this is called?

It is called an indirect instance of watching, noticing, or making a statement. you might also be thinking of quiet and sneaky instance of watching, noticing, or making a statement but that is when you sense something that is below the point where something begins or changes of the senses.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.