Question

7the mysterious glow of the fireflyfireflies (also called lightning bugs) are found in manydamp regions of asia and the americas. there are about2,000 different species of firefly. but how do these insects,which are actually a type of beetle, produce light, and whydo they do it? under the fireflys abdomen there is aspecial organ for producing light. when the insect takes inoxygen, it is combined in special cells with a substancecalled luciferin, and this makes that part of their bodiesglow. this light gives off almost no heat.the fireflies glow is necessary for their survival. forone thing, the blinking light is used to lure their prey. it isalso used as a warning sign to scare off predators.perhaps the most essential purpose of the fireflys glow isto attract a mate. if you ever watch fireflies, you will seethat their light flashes in various patterns, rather thansteadily. each species has a unique pattern of flashing.because of this unique pattern, fireflies are able to findmates within their own species. scientists have not yetdiscovered how fireflies can turn the glow on and off.which word or phrase from the passage above hints at a cause - and - effect relationship?a. because ofb. warning signc. perhaps

Explanation:

• Option A: "because of" is a common phrase used to indicate a cause - and - effect relationship. It shows that one thing (the cause) leads to another thing (the effect).
• Option B: "warning sign" is just a description of something (a sign that warns), it does not imply a cause - and - effect relationship.
• Option C: "perhaps" is a word used to express uncertainty or possibility, not a cause - and - effect relationship.

Answer:

A. because of