Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates?.

The distance d that a car can travel in a certain amount of time t can be found by multiplying the rate of speed r by the travel time. if a car has already travel 4 miles, the formula for the total distance travel is d= rt + 4. which of the following gives the value of r, in terms of d and t?

17 a tourist was planning a trip by car for travelling at some constant speed for 2.5 hours. however, he found that if he increases the speed by 20 km/h he can cover the same distance in 30 minutes less time than it was planned. what was the planned speed of the tourist, in km/h?

Nathan is an ecologist. he’s studying the effect of secondary consumers on primary consumers. his current research focuses on a population of blue jays and crows. they eat caterpillars and mice. if the number of blue jays increases, what are the likely effects on other populations? 1the number of crows will increase. 2the number of mice will decrease. 3the number of mice will remain the same. 4the number of caterpillars will decrease.