Question

in anaerobic respiration
water is a reactant
oxygen is absent
lactic acid is a reactant
oxygen is present

Explanation:

Anaerobic respiration occurs without the presence of oxygen. Water is not a reactant in the general sense of anaerobic - respiration reactions. Lactic acid is a product in some types of anaerobic respiration (e.g., in muscle cells during strenuous exercise), not a reactant.

Answer:

oxygen is absent