4.) Breathing rate is constantly being monitored and adjusted in the human body, which results in *
(1) the differentiation of mature body cells
(2) feedback mechanisms removing damaged cells
(3) modification of gene activity in cells
O (4) the internal environment being kept within certain limits

What link in the chain of transmission is described in the paragraph? sarah has been eating and sleeping poorly. she was just diagnosed with pneumonia. tests showed the illness was caused by streptococcus pneumoniae. in the chain of transmission, sarah is the (blank) , and streptococcus pneumonia is the (blank).