Complex sentence: The increase of their food supply (sebaceous glands proliferate during puberty) explains the increase of infestations of mites during adolescence.25% of the people who are up to 20 years old have mites, and 30% of people up to the age of 50 have mites.
Split into simpler sentences: The increase of their food supply (sebaceous glands proliferate during puberty) explains the increase of infestations of mites during adolescence. Twenty-five percent of the people who are up to 20 years old have mites, and 30% of people up to the age of 50 have mites.