Answer: C) Layer 4 Explanation: A reliable Transport layer connection uses acknowledgments to make sure all data is transmitted and received reliably. A reliable connection is defined by a virtual circuit that uses acknowledgments, sequencing, and flow control, which are characteristics of the transport layer.

Answer: C) Spider Explanation:

Answer: D) a growing recession Explanation: A low trough is indicative of "a growing recession" since a trough indicates a general change in the business cycle, which can have varying degrees of importance. A recession could be an important decline in economic activity that goes on for quite many months.