Question

read the text. the flying beetle known as the firefly or lightning bug is named for its most noticeable feature: its nighttime bioluminescence, or glow. the fireflys light - producing organ contains calcium, the pigment luciferin, the light - producing enzyme luciferase, and the chemical adenosine triphosphate (atp). when oxygen is added to this mix, it creates light, and the insect glows. scientists dont fully understand how the firefly makes its light blink, but one theory is that the firefly turns the light on and off by controlling the input of oxygen into the light - producing organ. which organizational structure does this text primarily use? cause - effect compare - contrast

Explanation:

The text first describes the components in the fire - fly's light - producing organ. Then it states that when oxygen is added to this mix, light is created (cause: adding oxygen; effect: light creation). It also mentions the theory about controlling oxygen input to turn the light on and off, which is another cause - effect relationship. There is no comparison or contrast of elements in the text.

Answer:

cause - effect