State a hypothesis based on the following questions:

what type of rocks do you think are present in your area?

is one rock more common than another?

why do you think this is so?

what do you think the streak will look like in your rock samples?

do you think the rocks will be hard or soft?

do you think calcium carbonate is present?

The area in which I live in is the Tikvesh valley, Macedonia. The rock types that dominate in my area are of two types, shale and andesite. The dispersal of these two totally different types of rocks is pretty much the same, so there isn't one that would dominate over the other. The reason why these two types of rocks are dominant in the area is because the area was underwater until 20 million years ago, so once the big lakes dried out, there were large layers of sedimentary rocks behind it, thus the shale. On the other hand, until 2.5 million years ago there was a volcano in the southern part of the area. The volcano had andesitic magma, so around the area where it was located there's predominantly layers of andesite. The streak in the rock samples is very simple, as they have very monotonous structure, their layers are not distinguishable when cut through. The shale is a soft rock, and it can be broken very easily, even by hand. The easiest way to break it though is to hit it with sharp object horizontally. The andesite is very hard rock, as it is an igneous rock. It has a much more solid structure, so breaking it is very hard. The presence of calcium carbonate in the area is lacking.

what's the question?

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: