Sooo i suck at science like a lot . even tho i have a 70.can someone help me pls?

it is A

Explanation: the only way to possibly know that is if they are in the same level or if the dinosaur bones were found above the level of trilobites

the answer is 303.15 or 303

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.