Tertiary consumer because you have no predators trying to eat you. You are at the top of the food web
No, not every scientific method begin with an observation. on basis of what we want, steps for scientific method changes.
And in scientific method before observation, first we predict (what will happen in the experiment). after prediction we observe. Prediction is known as hypothesis. And observation is what we are viewing.
EM waves can be expressed in:
Frequency, Wavelength, Intensity, Energy. etc..
Hope this helps!
