Answer:
a pencil being sharpened
freezing water
boiling water
Explanation:
a physical change doesn't change the chemical structure of an object. That is why the other 2 are wrong
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.
Can you be more specific?
...Diamond is the best conductor of heat, but heat also transmits readily through many other substances. Do you have multiple choice?
The correct answer is - b. If available resources decrease, then competition will increase.
All living organisms in an ecosystem are specialized in accordance to the living conditions and the food sources available. If a given ecosystem experiences prolonged drought, than the resources will decrease. With a decrease in resources, the living organisms will find themselves in a situation of scarcity. That will lead to a much increased competition, with both organisms of different species, and members of the same species. That will most likely lead to a situation where only the fittest will survive, while the weaker members of the species will probably die in that period of prolonged drought as they will not be able to get the resources they need to survive.