Final answer:
The six most abundant elements dissolved in seawater include chlorine and sodium, which combine to form sodium chloride, commonly known as table salt. Hydrogen and oxygen, elements of water, are also prevalent in the universe.
Step-by-step explanation:
The six most abundant elements dissolved in seawater are chlorine (Cl-), sodium (Na+), magnesium (Mg2+), sulfur (S), calcium (Ca2+), and potassium (K+). The two most abundant of these are chlorine and sodium. When chlorine and sodium combine, they form sodium chloride (NaCl), which is the chemical name for table salt.
Regarding water itself, it's a combination of hydrogen and oxygen, which are elemental components of water molecules (H2O). These elements are also some of the most abundant in both seawater and the universe.