In this question, the subject is "each of the players," which is singular. So, the singular form "possesses" (choice C) should be used. Choice A (possess) and choice B (have) are plural forms, and choice D (possessed) changes the tense to the past.

In this question, the subject "each" is singular, so the singular form "brings" (choice B) is the appropriate option. Choice A (bring) is the plural form, choice C (brought) is in the simple past tense, and choice D (has brought) is a singular form in the present perfect tense that is less appropriate in this context.

This question is testing subject-verb agreement in a sentence using "neither... nor..." construction. The verb should agree with the nearer subject, which is "teacher" in this case. Since "teacher" is singular, the verb "is" (choice B) should be used. Choice A (are) is the plural form, choice C (were) changes the tense to the past, and choice D (has been) opts for the present perfect tense.

The subject "nutritious meals and regular physical activity" is plural, so the correct verb form is "help alleviate" (choice B). Choice A (helps alleviate) is the singular form, while choices C (helped alleviate) and D (will help alleviate) use incorrect tenses.

This question is testing subject-verb agreement with the subject "discovery." Since "discovery" is singular, the singular form "marked" (choice B) should be used. Choice A (mark) is the plural form, choice C (has marked) opts for the present perfect tense, and choice D (were marking) changes the tense to the past continuous.