An Unhealthy pH Level. Tooth decay can occur when the pH level in the mouth is 5.5. For reference, the neutral level is 7.0. When we consume acidic foods and drinks, the pH within the mouth decreases and can cause the pH in the dental plaque to fall rapidly below 5.0.
Plastic Golden Age Passports are valid for a lifetime. However, if you do want the new Senior Pass, you may purchase one for $10, with proof of identification (e.g., driver's license, birth certificate, or similar government-issued document).lastic Golden Age Passports are valid for a lifetime. However, if you do want the new Senior Pass, you may purchase one for $10, with proof of identification (e.g., driver's license, birth certificate, or similar government-issued document).
Best Answer: An adult passport is good for 10 years, while a child's passport is good for 5 (age 15 and under).Keep in mind that many countries will not let you travel if there isn't at least 6 valid months before your passport expires. Source(s): Just a friend.est Answer: An adult passport is good for 10 years, while a child's passport is good for 5 (age 15 and under).