Please help ASAP! Super comfused on how to solve these three environmental engineering problems. Refer to image below.

$(4$ points$)$ You are reviewing the risk of benzene exposure by your employees. You know that the concentration of benzene in the air in your facility is $1m\frac{g}{m^3}.$ Your employees are exposed to this concentration in $8$ hour shifts for each of $250$ days per year based on their work schedules. You have a low turnover rate, so the average worker gets this exposure for $20$ years. Using the values from Table $6-7,$ assuming your employees are adult females, what is the chronic daily inhalation intake of benzene in $m\frac{g}{k}g*d?$ Assume the averaging time is $27,375$ days.

$(3$ points$)$ What particles are emitted in each step of the decay chain represented by ${?}_{92}^{238}Ulongrightarro{w}_{90}^{234}Thlongrightarro{w}_{91}^{234}Palongrightarro{w}_{92}^{234}U?$

$(3$ points$)$ A hospital needs to dispose of a waste containing $100C\frac{i}{L}$ of ${?}^{131}$I. How long must it be stored until it decays to a radiation activity of$15C\frac{i}{L}?$