a. If s21 represents the larger of two sample variances, can the F test statistic ever be

Question:

a. If s21 represents the larger of two sample variances, can the F test statistic ever be less than 1?
b. Can the F test statistic ever be a negative number?
c. If testing the claim that σ21 ≠ σ22 what do we know about the two samples if the test statistic is F = 1?