It has been theorized that all of the modern continents on Earth were once part of a single continent. What scientific evidence is used to support this theory? 1) Fossils of similar lifeforms have been found on different continents.

2) The coastlines of some modern continents appear to have once fit together.

3) Some of the continents that exist today have similar types of rocks.

Which on is it?

2) The coastlines of some modern continents appear to have once fit together.

Explanation:

Because it is true if you look at a map you can clearly see that some continents fit together perfectly. It is quite amazing.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.