In most developed countries, large fish kills and contamination of drinking water may be caused by all of the following except malfunctioning sewage treatment plants

Malfunctioning sewage treatment plants

accidental release of toxic industrial chemicals

pesticides and plant nutrients from agricultural sources.

accidental release of predatory exotic species

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.