Practice B. For each case, determine the two variables and tell whether the relationship is positive or negative. 1. The more time is spent in studying his lessons, the higher is the average grade of Nelson. 2. If the population of fox in the forest increases, the number of deer decreases. 3. The more students enroll in a school, the more teachers are needed. 4. As a person ages, his memory decreases. 5. The more workers are hired to paint the whole school, the sooner the job is done