Absence for parental-approved activities. This category of absence will be counted as excused for purposes agreed to by the principal and the parent/guardian. The principal or designee may excuse no greater than five days per school year. An absence may not be approved if it causes a serious adverse effect on the student's educational progress. In participation-type classes (e.g., certain music and physical education classes) the student may not be able to achieve the objectives of the unit of instruction as a result of absence from class. In such a case, a parent or guardian approved absence would have an adverse effect on the student's educational progress which would ultimately be reflected in the grade for such a course. A student, upon the request of his/her parent/guardian, may be excused for a portion of a school day to participate in religious instruction provided such is not conducted on school property or otherwise involves the school to any degree.