What statement applies to the rate of frequency at which monozygotic (identical)twins are born?

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There can be differences in the behaviours between identical and fraternal twins.There is near-unison in the actions of identical twins (although they alternate in assuming the leadership),but fraternal twins,even of the same sex,do not display this quality.The tendency toward monozygotic twins is unaffected by heredity.Monozygotic twins are not affected by maternal age,but higher-order births are.Multiple births occur with variable frequency and are not uniform among any particular population or race.

What Statement Applies to the Rate of Frequency at Which