Does the Sun pass through the vernal equinox every year on the same date in March? If not, then why, and to what extent can

Does the Sun pass through the vernal equinox every year on the same date in March? If not, then why, and to what extent can this date change? Note: Remember the calendar device.

It fluctuates from March 20 to March 21 with a four-year leap year period.

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