turkeys exhibit aggressive parental protective behaviors that are triggered by the cheeping sound of their young chicks. what term best applies to this behavior?

a) sign stimulus
b) operant conditioning
c) imprinting
d) classical conditioning

volcanoes (an event in the geosphere) release a large amount of particulate matter into the atmosphere. these particles serve as nuclei for the formation of water droplets (hydrosphere). rainfall (hydrosphere) often increases following an eruption, stimulating plant growth (biosphere).

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?