12. Copper has 2 main isotopes, Cu-63 and Cu-65. Look up copper's atomic mass on the periodic table. a) Which isotope, Cu-63 or Cu-65, is most abundant in nature?
b) Explain how you can tell.

Is there any opitions? if you have the periodic table, the noble gases are 8a family, the halogen are the 7a family, and the nonmetal are  carbon, nitrogen, phosphorus, oxygen, sulfur, selenium, fluorine, chlorine, bromine, iodine and astatine.

Question 1 answer: make sure you eat healthy foods and excercise atleast once a day.question 2 answer: sometimes bullying . bullying lowers a persons self-esteem sometimes which can make them not care for themselves to much making them feel bad about there body structer. that or they just have a bad body structer and there family/doctor said its unhealthy how they eat.