People's hair are curly because of there genes they get ot from there gray gray Gary grandma or granpas
In my opinion, it always depends on the partner how they are going to maintain their healthy relationship.
But for my opinion, here are the top 3 ingredients for a healthier relationship:
1. Communication - it is always important that you and your partner are being open with each other and being honest
2. Trust - trust is one of the most important and essential ingredients of healthy relationships
3. Commitment - how can you be in a healthy relationship if you are not commited?
Answer:
natural selection is the answer
Tectonic plates, is probably the answer
<em /> I believe it's gravity.