To restore nitrogen to the soil, fields should occasionally be planted with what

Legumes

Explanation:

Legumes, leguminous plant that belong to Fabaceae botanical Family (e.g. beans, peanuts, turnips, cloves) , are excellent for restoring the fertility of the soil as they can increase nitrogen soluble compounds within the soil.

They manage to do so because they can establish symbiotic relationships with nitrogen fixing bacteria present in its root nodules. These particular bacteria (e.g. cyanobacteria) can take atmospheric (gaseous) molecular nitrogen and fixed it. This means that these bacteria can transform gaseous nitrogen into a soluble compound that can be retained by water within soil and thus can be absorbed by plant roots.

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.

69 is the correct math for the amino acids