Which statement is true about the types of chemical elements in living cells? a. animal cells and plant cells contain very different elements b. very few cells contain either carbon or oxygen c. all cells contain the same key elements such as carbon, nitrogen, and oxygen d. single cells organisms have different types of elements from multicell organisms

Match the following terms describing electrical events with the correct phases of the cardiac cycle. the ventricular muscle cells depolarize at the start of this phase. during this phase, na+ entry through the funny channels causes the pacemaker potential of sa nodal cells to gradually become less negative until it reaches threshold. the ventricular muscle cells repolarize right before this phase. the cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. a. isovolumetric relaxation b. ventricular ejection c. isovolumetric contraction d. ventricular filling

Where do the respiratory and circulatory systems meet? a. in the heart b. in the muscles c. in the lungs d. in the brain

Iwill mark brainliest and all that sha-bang. what is the function of the endocrine system? a. control longer term response in the body. b. transmit messages throughout the body. c. remove waste from the body. d. all of the above