Taigas, tundras, and tropical rainforests share what common abiotic component.

Two technicians are discussing how to test a car's exhaust by holding a small piece of paper within an inch of the tailpipe mouth. technician a says that if the paper is vibrating due to a "puffing" output from the tailpipe, this signals a smoothly running engine. technician b says that if the paper is being drawn toward the tailpipe, this could indicate burned exhaust valves. who is correct? a. technician b b. both technicians a and b c. technician a d. neither technicians a or b

Anna’s mother prepares sauerkraut, a fermented dish made from finely cut cabbage and salt. lactobacillus bacteria present on the surface of the cabbage combine with salt to turn the cabbage into a crunchy, sour dish. what chemical process occurs to create this dish? a. alcoholic fermentation b. cellular respiration c. conservation d. lactic acid fermentation e. photosynthesis

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.