Based on the information in this passage, which of the following is a reasonable conclusion?

A) Scientists will never change the classification system again.
B) Scientists know everything there is to know about all organisms.
C) Scientists have never changed the classification system.
D) New scientific discoveries could change the current classification system.

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?

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

Based on anatomical similarities, to which modern animal is dr. digger’s creature most closely related?