What is this element?
a. beryllium b. nitrogen
c. lithium d. carbon

what is the mass number for the element above?
a.10 b.7 c.6 d.4

A lithium atom contains 3 protons in its nucleus. Notice that because the lithium atom always has 3 protons, the atomic number for lithium is always Z = 3. The mass number, however, is A = 6 for the isotope with 3 neutrons, and A = 7 for the isotope with 4 neutrons.
so most Likely your answer should be...

C. Lithium

I’m guessing you’re more alert to yourself or your surroundings if you’re more concentrated

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .