Which is the correct direction of blood flow?
Question 1 options:

right atrium --> right ventricle --> pulmonary artery

left ventricle --> left atrium --> aorta

right atrium --> left atrium --> pulmonary artery

left ventricle --> pulmonary artery --> aorta

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass

  like australopithecus afarensis; probably the direct ancestor of this group. africa: 5.8 to 4.4 million years ago.