Which of the aforement unique characteristics of earth do you like the most and why?

The Earth rotates on its axis at a constant tilt.

Earths rotation on its axis at a constant tilt provides seasonal changes in the different part of the country. This resulted to the distribution of the heat of the sun from northern hemisphere and to southern hemisphere. Making areas with hot temperature may experience rainy season in a year. This will help production of crops or food supply and water supply available for living organism.

If the Earth's rotation is not tilted, then both the northern hemisphere and southern hemisphere will be covered with thick ice sheet. The equatorial region or near the equatorial region will experience tremendous warm temperature. Making our life on Earth not ideal for living.

Magnetic Field

Earth is protected by the magnetic from the dangerous radiation coming from the heat of the sun.

Water and oxygen

These two elements are essential for living organism in order to survive. The existence of waters proves that Earth temperature is conducive for living.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

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.