Give a short explanation to describe the dangers from drinking contaminated water and name FOUR diseases that can be contracted from contaminated water.​

In the context of it jobs in the information systems field. a is responsible for database design and implementation

Match each vocabulary word to its definition.1. desktoppicture used to represent acomputer application2. domainnetwork protectionsoftware code that can be viewed,3. iconmodified, and redistributed for freethe background screen on acomputer monitor4. url5. blogan online journalthe part of an internet address that6. firewallrefers to a group of computers on anetworkonline database of web pages7. intranetnetwork for use by an individual8. open address of a web page or9. wikiresource

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?