I picked Biology as the subjectthere is no subject classification listed for Geology. How long ago did the Molten surface of the earth cool to form the crust?

Around 4.54 billion years ago

Explanation:

The first rocky bits of Earth coalesced around 4.54 billion years ago, less than 100 million years after the solar system formed. For much of those early years, Earth was a blob of molten rock, but over time, the surface cooled and formed a crust that floated on the Earth's liquid core

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.