Meaning: 'Rise' refers to an increase or emergence of something, in this case, light pollution.

Wrong options:

• suppose: 'Suppose' is a verb that means to assume or believe something, which does not fit the grammatical structure needed here as it does not indicate causation.
• boom: 'Boom' is a noun that refers to a rapid increase, but it does not fit the phrase 'has given ___ to' as it is not commonly used in this context.
• insist: 'Insist' is a verb that means to demand something forcefully, which does not fit the grammatical structure or context of the sentence.
• rely: 'Rely' is a verb that means to depend on, which does not fit as it does not indicate an increase or emergence.
• face: 'Face' is a verb that means to confront or deal with, which does not fit the context of causation needed here.

Correct answer: rely

Explanation: The word 'rely' is a verb that indicates dependence on something, which is appropriate in this context as it describes species that depend on natural light and dark cycles for their survival. The grammatical structure requires a verb that fits with 'species that ___ on.'

Meaning: 'Rely' means to depend on or trust in something, in this case, natural light and dark cycles.

Wrong options:

• suppose: 'Suppose' is a verb that does not fit the context of dependence as it implies assumption rather than reliance.
• rise: 'Rise' is a noun that does not fit the grammatical structure needed here, as it does not indicate dependence.
• boom: 'Boom' is a noun that does not fit the context of species depending on something, as it refers to an increase rather than reliance.
• insist: 'Insist' is a verb that does not convey dependence and does not fit the context of the sentence.
• face: 'Face' is a verb that means to confront, which does not fit the context of dependence on natural cycles.

Correct answer: face

Explanation: The word 'face' is a verb that indicates confronting challenges, which is appropriate in this context as it describes the ecological challenges that sea turtles encounter due to artificial light. The grammatical structure requires a verb that fits with 'turtles ___ ecological challenges.'

Meaning: 'Face' means to confront or deal with something, in this case, ecological challenges.

Wrong options:

• suppose: 'Suppose' is a verb that does not fit the context of confronting challenges, as it implies assumption rather than action.
• rise: 'Rise' is a noun that does not fit the grammatical structure needed here, as it does not indicate confronting challenges.
• boom: 'Boom' is a noun that does not fit the context of facing challenges, as it refers to an increase rather than confrontation.
• insist: 'Insist' is a verb that does not convey the action of confronting challenges and does not fit the context of the sentence.
• rely: 'Rely' is a verb that indicates dependence, which does not fit the context of confronting challenges.