1 Coming-of-age day in Korea has / doesn't have a serious side.
2 Foreign people can only watch / watch and take
part in the ceremony.
3 At one point in the ceremony, parents and children
do similar / different actions.
4 The festival is both serious and fun / basically
serious.
5 These days, young people can/can't choose
between modern and traditional gifts.
6 The traditional festival is losing popularity / as
popular as ever.

1 Coming-of-age day in Korea has a serious side.

2 Foreign people can watch and take part in the ceremony.

3 At one point in the ceremony, parents and children do similar  actions.

4 The festival is both serious and fun.

5 These days, young people can choose between modern and traditional gifts.

6 The traditional festival is losing popularity.

Explanation:

Coming-of-age day is a special day that marks the moment when individuals stop being children and become adults. This day is held through a ceremony where everyone wears traditional Korean clothes and bow towards their country in thanks for their care in childhood. Parents, in turn, bow towards their children, showing respect for the adult life they will have. Although this ceremony is losing its popularity it is still possible to see it being performed, including the participation of foreigners who can attend and participate in the activities.

It is a tradition that on that day young people get flowers and perfume, but nowadays they are allowed to choose their gifts.

- "these rights are natural and god-given to all men equally." (i disagree cuz i kind of think it's 'a' but who knows.)

the simple predicate of the sentence is camped.