During the 19th century, sea otters were hunted almost to the point of extinction. when the number of sea otters became very low, the ecosystem of kelp bed "forests" also declined. scientists discovered that the sea otters were predators of sea urchins, which were, in turn, predators of the kelp. when sea otters declined, the sea urchin populations grew, destroying the kelp ecosystem and the many species that depended on it. it was then understood that sea otters were in this ecosystem.
d. a keystone species
A keystone species is the one that determines the structure, function and other aspects of the entire community. Other species of the system are greatly affected by keystone species. The keystone species are mostly not the most abundant ones but regulate the species richness and ecosystem functioning by affecting the availability of food, water or other resources.
In the given example, sea otters determine the species richness of kelp bed forests. By regulating the sea urchin population, they affect the population size of kelp as well. Removal of sea otters from the system destroyed the whole ecosystem. This makes sea otter a keystone species for the given ecosystem.
d. a keystone species
A keystone species plays a very important role in an ecosystem. It is crucial in maintaining the health of the ecosystem and without it the ecosystem would collapse.
Here, the otter species had an important role in keeping check on other species. It indirectly maintained enough number of kelp bed forests by consuming sea urchins since sea urchins consumed kelp. Without sufficient number of otters, sea urchins grew indiscriminately which lead to increase in consumption of kelp. Kelp population decreased when sea otter population decreased. Hence, sea otters were keystone species in this ecosystem.
d is the answer
sorry if its wrong!
the answer is; comparing the frequency of collisions with and without the device
this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.