The atoms found in living tissues all have complete outer electron shells and are therefore quite stable on their own.

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.

i got something better   a catchphrase here it is

ahem  

ahem

what the squwock

explanation:

nucleus

would be most reasonable answer tbh

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]