Which condition might be treated with a pacemaker? A. hemorrhagic stroke

B. atherosclerosis

C. heart failure

D. arrhythmia

What’s this animal (picture is tagged) and where is it most likely to live, rainforest or desert?

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

Which is the correct order in the scientific process? ask a question ® form a hypothesis ® make an observation ask a question ® make an observation ® form a hypothesis make an observation ® form a hypothesis ® ask a question make an observation ® ask a question ® form a hypothesis