Put the stages of the formation of a dead zone in their correct order. Large number of fish and other marine life die, surface biomass blocks sunlight and prevents photosynthesis, high levels of microbial activity consume oxygen, excessive amounts of nitrogen and phosphorus promote aggressive biomass growth, surrounding water becomes hypoxic or anoxic, root vegetation and phytoplankton decompose.

Acurium-245 nucleus is hit with a neutron and changes as shown by the equation. complete the equation by filling in the missing parts. 52

Agroup of students is studying convection current. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other is in an area with warm air. after 10 minutes, the balloon are released from a height of 1 meter. which of the following to the students most likely observe? a) the warm balloon expands and rises. the cold balloon shrinks and sinks b) the balloon both rise. the cold balloon is larger than the warm balloon c) the cold balloon expands and rises. the warm balloon shrinks and sinks d) the balloon rise at the same rate. both balloons are the same size

12. calculate the hydroxide ion concentration of a solution with ph = 3.25. show all calculations leading to an answer