Which evidence did ottowa scientists collect in researching pcb concentrations in alaska?

a) pcbs were found in smaller concentrations in lakes where more salmon spawned.
b) pcbs were found in the same concentrations in lakes at similar altitudes.
c) pcbs were found in greater concentrations in lakes where more salmon spawned.
d) no pcbs were found in the lakes that were farthest from electronics industry dumping grounds.

What produces light and all other electromagnetic waves? a) the photoelectric phenomena b) heated metals c) charged particles d) radioactive samples (pls explain if you can : )

You are driving directly behind a pickup truck, going at the same speed as the truck. a crate falls from the bed of the truck to the road. (a) will your car hit the crate before the crate hits the road if you neither brake nor swerve? (b) during the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck?

Consider a file currently consisting of 200 blocks. assume that the file control block (and the index block in the case of indexed allocation) is already in memory. calculate how many disk i/o operations are required for contiguous, linked, and indexed (single-level) allocation strategies, for each of the conditions listed below. in the contiguous-allocation case, assume that there is not room to grow at the beginning but there is room to grow at the end. also assume that the block information to be added is stored in memory.