Radiation from the sun goes to earths atmosphere this is called what

Ineed to find the answer of this question because i dont understand it

Element before carbon on the periodic table

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided