How does Digestion relate to diabetes?

What is thought to have caused the mass extinction at the end of the cretaceous period?

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled

Brass gets discoloured in air because of the presence of which of the following gases in air? a. oxygen b. hydrogen sulphide c. carbon dioxide d. nitrogen