c. aphotic is a zone where no light penetrates. the others all include organisms in their definitions.
its in leaves
have agoed day
the correct answer would be 57.
atomic number is defined as the total number of protons in an atom. thus, the number of protons in element x would be 29.
in addition, the mass number is defined as the sum of neutrons and protons present in an atom.
therefore, the sum of the number of neutrons and protons in an element x would be 86.
thus, the number of neutrons = mass number- the number of protons
hence, the number of neutrons would be equal to 57.