NEED HELP ASAP REALLY BEHIND

1: Sensory organ detect stimuli

2: The communication system send the impulse to control centre.

3: the controle centre receives the impulse process it.

4: controle system send message from controle system to target.

5: target cells react.

Explanation:

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.

the median of the data is 4.5.