Answer:
The answer is "Cell Membrane".
Law would be the correct answer to fill in the blank. Law is correct because scientific law explains behaviors of natural phenomenons since it's based on repeated experiments.
ionic bonding.
Ionic bonding<span> is a type of </span>chemical bond<span> that involves the </span>electrostatic attraction<span> between oppositely charged </span>ions<span>, and is the primary interaction occurring in </span>ionic compounds<span>. The ions are atoms that have gained one or more </span>electrons<span> (known as </span>anions<span>, which are negatively charged) and atoms that have lost one or more electrons (known as </span>cations<span>, which are positively charged). This transfer of electrons is known as </span>electrovalence<span> in contrast to </span>covalence<span>. In the simplest case, the cation is a </span>metal<span> atom and the anion is a </span>nonmetal<span> atom, but these ions can be of a more complex nature, e.g. molecular ions like NH</span>4+<span> or SO</span>42−<span>. In simpler words, an ionic bond is the transfer of electrons from a </span>metal<span> to a </span>non-metal<span> in order to obtain a full valence shell for both atoms.</span>
An ancient horse was used for labor and was made for carrying heavy loads of water horses are now built with more muscle in their legs