Please answer these questions for me. 10 A. How many years would pass if only 25% of the Potassium-40 radioactive elements are left?

10B. How many half-lives has the sample gone through if only 25% of the Potassium-40 radioactive elements are left?

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times

answer: 45

explanationyou have to add as well to be it could be

1. a host loses nutrients to a parasite

2. a parasite only benefits when the host is alive (cause if the host dies the parasite dies with it )

3. producers to consumers

4. the tapeworm is a parasite

5. they convert energy from the sun (photosynthesis)

6. sunflower-robin (i think im 80% sure)

7. producer

8. consumer

9. prey

10. fresh water snails ( cause the green algea is the producer and the snails are the primary consumers and the small fish consumer so is the big fish)

voluntary muscles are controlled by the cerebellum.