Um átomo x possui 8 neutrons e seu número atômico e igual a 8. sabendo que esse atomo é isótopos de y, que possui número de massa 18, responda: qual o numero de nêutrons do atomo y ?

Isotopes are defined as the atoms which have same number of protons but different number of neutrons of same element. Since the proton number is same, the atomic number also same. Hence the atomic number of Y is 8.

Mass number = atomic number + neutron number

                   18 = 8 + neutron number

Neutron number = 10

Hence, there are 10 neutrons in Y.

i think its 100

i hope this !

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.