What do you know about a chemical compound by looking at its chemical formula ?

The answer is the number and kinds of atoms in the compound.

In an ionic compound, the formula gives the ions and their ratios in the crystal lattice. In a molecular compound, the formula gives the numbers of atoms of each element in a molecule.

answer: all : )

explanation:

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]