Please capitalize where necessary: a follow-up experiment could be conducted to investigate factors influencing enzyme activity (such as temperature, ph and the concentrations of enzyme, substrate and product).
A: A follow-up experiment could be conducted to investigate factors influencing enzyme activity (such as temperature, pH and the concentrations of enzyme, substrate and product).

Q: there will be a 15 usd charge per 15 minutes for a late check-out.

A: There will be a 15 USD charge per 15 minutes for a late check-out.

Q: in 2009, for the first time since its opening, the bridge experienced a 2.0 per cent decline in vehicle traffic.
A: In 2009, for the first time since its opening, the bridge experienced a 2.0 per cent decline in vehicle traffic.

Problem: sygp: number of persons with contacts covered by public health insurance by region, type of benefits, age, sex and socioeconomic status
Can you repeat this sentence, but capitalize it?
Answer: SYGP: Number of persons with contacts covered by public health insurance by region, type of benefits, age, sex and socioeconomic status

Text: skis, golf bags and other sports items

Correct capitalization: Skis, golf bags and other sports items

Problem: but the man said, "i don't know . there must be a way to breathe under water. and there must be a way to give everybody something to eat.
Can you repeat this sentence, but capitalize it?
Answer:
But the man said, "I don't know . there must be a way to breathe under water. And there must be a way to give everybody something to eat.