Show how to make a ten to solve 13-7. write the number sentence.

-7 + 3 + 10 = -4 + 10 = 10 - 4 = 6. 

To turn 13 into 10, you need to break it up into 10 + 3, which does not change the value of 13. Then, you add 3 to -7, which results in -4. Next, you add -4 to 10 (or rather, subtract 4 from 10), which results in 6. 

The answer is biodiversity resulting from new ancestors.

These are the multiples of 15 but what you are probably asking or what are the factors of 15