The scientific method is a process of steps in order to get a conclusion. First, a scientist will observe something. It could be really anything. Then he/she will ask themselves a question. Like how does it do that? Or why does it do that?
Then they will form a hypothesis. This is where you will ask yourself what will be the outcome of the experiment.
Next you actually perform the experiment. If the experiment comes out as your hypothesis predicted, then you accept your hypothesis.
If not, you reject your hypothesis.
Of course, in science you just don't do one experiment. You do it multiple times and even with different circumstances.
Commensalism is when one organism benefits off the other one without harming it. Examples are tree frogs that use plants for protection or jackals that have been expelled from packs trailing tigers and feeding on the remains of its kill. Barnacles on whales get shelter by attaching to a whales body
Octopus and squid have chemoreceptors on their tentacles. The correct option is the third option.
The head at the top, the tail is just for getting to the egg