Answer:
Do children's heart rates increase at the same speed when walking uphill?
Does temperature affect how long blood can be stored?
How does moisture affect the growth of moss on a tree?
Explanation:
A testable hypothesis can be developed for all of these questions because they are scientific and plausible. A testable hypothesis cannot be developed from "Which of Leeuwenhoek’s microscopes was the coolest?" and "Is experimenting with moldy bread more fun than experimenting with yogurt cultures?" because they are opinionated questions, and therefore not scientific.
