The correct answer is option C, that is, hypothesis.
The hypothesis is the starting building block in the scientific method. It is also illustrated as an educated guess, based on previous observation and knowledge. A hypothesis refers to a recommended solution for an unexplained event, which does not fit into the present accepted scientific theory.
The fundamental concept of a hypothesis is that there is no pre-determined result. For a hypothesis to be considered as scientific hypothesis, it has to be something, which can be refuted or supported via carefully crafted observation or experimentation.
Answer: The correct answer is option (D)
Explanation:
These aurora are also known as polar lights or northern lights( north poles) or southern lights(south pole) . This is caused by the interaction between the charged particles from the sun with particles present in the upper atmosphere of the earth's atmosphere. The layer in which these interaction takes place is Thermosphere (with high temperature).
Hence, the correct answer is option (D).
<span>Soil is partially the result of the physical and chemical weathering of its parent rock. The minerals found in the soil were either in that parent rock, or they were formed from the weathering products of the parent rock.</span>
Explanation:
Reaction equation showing alpha decay in Uranium-238 is as follows.

It is known that an alpha particle is basically a helium nucleus and it contains 2 protons and 2 neutrons.
Symbol of an alpha particle is
.
As atomic mass or weight is the sum of total number of protons and neutrons present in an atom.
Hence, the atomic weight of the alpha particle is (2 + 2) = 4.