Meaning: 'Leads' means to guide or direct towards a particular outcome or idea.

Wrong options:

• course: 'Course' is a noun and does not fit grammatically as a verb in this context.
• period: 'Period' is a noun that does not relate to the action of guiding or directing.
• effort: 'Effort' is also a noun and does not serve as a verb to indicate action in this sentence.
• guide: 'Guide' is a verb but does not fit the context as it implies a different meaning than 'leads.'
• race: 'Race' is a noun and does not fit grammatically as a verb in this context.
• predicting: 'Predicting' is a gerund and does not fit as a main verb in this sentence.

Correct answer: predicting

Explanation: The gerund 'predicting' fits grammatically as it serves as the object of the preposition 'for,' indicating the purpose of the principle of cause and effect.

Meaning: 'Predicting' refers to the act of forecasting or anticipating future events based on current knowledge.

Wrong options:

• course: 'Course' is a noun that does not fit as an action or purpose in this context.
• effort: 'Effort' is a noun and does not relate to the action of forecasting events.
• leads: 'Leads' is a verb and does not fit as a noun in this context.
• guide: 'Guide' is a noun and does not serve as an action or purpose here.
• race: 'Race' is a noun and does not fit the context of predicting events.

Correct answer: course

Explanation: The noun 'course' fits grammatically as it serves as the object of the preposition 'of,' indicating the type of action being chosen.

Meaning: 'Course' refers to a direction or path taken in a particular situation or decision-making process.

Wrong options:

• leads: 'Leads' is a verb and does not fit as a noun in this context.
• guide: 'Guide' is a noun that does not fit as it does not describe a type of action or decision.
• predicting: 'Predicting' is a gerund and does not fit as a noun in this context.
• effort: 'Effort' is a noun that does not relate to the type of action being chosen.
• race: 'Race' is a noun that does not fit the context of describing a course of action.

Correct answer: race

Explanation: The noun 'race' fits grammatically as it serves as the subject of the clause, referring to humanity as a collective group.

Meaning: 'Race' refers to a group of people sharing common physical or social qualities, in this case, humanity as a whole.

Wrong options:

• course: 'Course' is a noun that does not fit as it does not refer to a group of people.
• period: 'Period' is a noun that does not relate to the concept of humanity.
• effort: 'Effort' is a noun that does not fit the context of describing a collective group.
• leads: 'Leads' is a verb and does not fit as a noun in this context.
• predicting: 'Predicting' is a gerund and does not fit as a noun in this context.