for the high school’s production of "grease," 315 tickets were sold. the cost of a student ticket, s, was $5; the cost of all other tickets, t, was $8. the total income from ticket sales equaled $2211. the system of equations below can be used to determine the number of each type of ticket sold.

The graph shows a trend in an ecosystem over time caused by increased pollution in the region. what can you conclude from the graph? a. there’s lower biodiversity among birds. b. there’s a higher reproductive rate among birds. c. there’s a significant decline in the number of producers. d. other types of animals were unaffected by pollution.

Scientists observed a rock stratum with fossil. if mollusks evolved before arthropod, where will their fossils be found.

How do you work out 21.3-8= show your working. plz