the ages of rocks can be determined using the isotope 135cs, which undergoes beta decay with a half-life of 2.3×106 y. a rock sample contains a ratio of 135ba to 135cs of 0.15. given that 135ba is a stable product of the beta decay of 135cs, and assuming there was originally no 135ba present in the rocks, calculate the age of the rock sample.

These three organisms are interdependent on each other for their survival. what will happen if foxes are eliminated from the region? a. there will be more rabbits and less grass in the region. b. there will be more grass and fewer rabbits in the region. c. there will be fewer rabbits and less grass in the region. d. there will be more rabbits and more grass in the region.

Spider crabs live in the shallow regions of the ocean floor. algae tend to grow on the surface of spider crabs. the algae provide the crabs protection from predators by camouflaging them. the spider crabs give the algae shelter. what does this description suggest? 1. the algae are parasites of the spider crabs. 2. the algae and the spider crabs have a mutualistic relationship. 3. the spider crabs are commensals, and the algae are parasites. 4. the spider crabs benefit from the algae living on them. 5. the spider crabs are parasites of the algae.

Which of the following is not a need-based source of financial aid? question 7 options: a: athletic scholarship b: subsidized loan c: unsubsidized loan d: federal grant