An unknown element has a radioactive count of 400 counts per minute. If it has a half life of 12 minutes. How long will it take to reduce to 25 counts per minute? Show your working out and units in your answer.

What is the cause hearing loss in human being

The ancestors of plants that lived in water had plenty of water for the young. angiosperms are a group of land plants that evolved a reproductive trait for living on land. this trait protect young plants by allowing them to grow only when water is present and the conditions for healthy development are right. what trait most likely young angiosperms in this way?

49 ! how are energy cycles and growth cycles related?