sentence: Air is taken in through openings on the sides of the abdomen called spiracles.
sentences_before: Insect respiration happens without lungs. There is a system of internal tubes and sacs through which gases diffuse or are actively pumped.
sentences_after: As larvae, many insects have gills that can extract oxygen dissolved in water, while others need to rise to the water surface to replenish air supplies which may be held or trapped in special structures.
concept_name: air
headings: Insect Physiology Respiratory and circulatory systems
categories: Basic English 850 words