Explanation:
A chemical reaction is defined as the reaction in which bonds between the reactants either break or form which leads to the formation of a new substance.
For example, 
So, when we drop a sodium metal into water then it produces a frizzing sound which shows the metal is reacting with water.
We know that when two aqueous solutions chemically react with each other then it may lead to the formation of an insoluble substance which is known as precipitate.
This means that formation of a precipitate is also a chemical reaction.
Thus, we can conclude that following are the statements which show evidence for a chemical reaction.
- Dropping sodium metal into water produces fizzing.
- Mixing two aqueous solutions produces a precipitate.
Not sure how in depth or what level of particles but I will go as deep as I know. The matter that makes up the world is comprised of 12 particles which are known as fermions. There are 12 fermions which are made up of 6 quarks (up, charm, top, Down, Strange, Bottom) 3 electrons (electron, muon, tau) and three neutrinos (e, muon, tau). Technically, only the up quark, down quark, electron, and electron neutrino are necessary to create all known matter since others would simply be very unstable and decay into those particles. The other type of particles are known as Bosons. These particles transmit forces and all sorts of different interactions. I have included a photo from online which describes the main characteristics of each elementary particle.
Answer:
I am pretty sure the correct answer is a reproductive system
To determine the number of years for a person to live, we can divide the total number of beats in a lifetime to the number of beats per minute. We first need to check if the units are similar so we can cancel them. We do as follows:
3.1x10^9 beats / 68 beats per minute = 45588235.29 minutes ( 1hr / 60 min ) ( 1 day/24hr) ( 1 year / 365 days ) = 87 years
Hope this answers the question. Have a nice day.
