LIFE SCIENCE

Detailed explanation-1: -atom: The basic unit of matter; the smallest unit of an element, having all the characteristics of that element; consists of negatively-charged electrons and a positively-charged center called a nucleus.

Detailed explanation-2: -The atom is considered the basic building block of matter. Anything that has a mass-in other words, anything that occupies space-is composed of atoms.

Detailed explanation-3: -Atoms are the smallest units of matter that have all the characteristics of an element. Atoms combine to form molecules. Atoms are composed of smaller particles known as protons, neutrons, and electrons.

Detailed explanation-4: -Atoms are made up of even smaller subatomic particles, three types of which are important: the proton, neutron, and electron. The number of positively-charged protons and non-charged (“neutral”) neutrons, gives mass to the atom, and the number of each in the nucleus of the atom determine the element.