Salt because the products are H20 and NaCl. H2O evaporated leaving salt or NaCl as the remainder.
Explanation:
electrovalent bond covers single bond.
Covalent bond covers double or more bonds.
Trace fossils provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and feces left behind by animals, rather than the preserved remains of the body of the actual animal itself. so i would say B.
