Which of these results is an advantage of the green garden technology shown in the picture compared with other gardening practices

It conserves water

Explanation:

This is because the stones hold the water down from flowing to the street and the soil is able to use the water held efficiently.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.