For a total of 5 fractions, calculate the following: a. The number of events in a cell, assuming the cell survives the first 4 fractions b. The probability that a cell will be hit once and only once during the 5 fractions.A radiobiology experiment is performed in the porcine model. The tumor cells can be assumed to be spherical and have a diameter of 20 microns on average, and they occupy 20 cm . This volume is exposed to a uniformly distributed radiation that deposits a dose 2 Gy per fraction. The energy of the radiation is such that an active event corresponds to about 80 eV