An intertidal species of sea star helps to maintain the diversity of the intertidal region by controlling the mussel population. Without the sea star, the mussel population would crowd out other species and take over their territory. The sea star could be called a(n) .

Intertidal zones are the seashore areas above water and underwater level at low and high tides. They include organisms like crabs, mussels, anemones, palms etc.

The sea star could be called a keystone species.

Therefore sea-star is the keystone species.

To learn more about keystone species follow the link:

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The sea star could be called a(n) keystone species.

Explanation:

The concept of keystone species was introduced by zoologist Robert T. Paine, in 1969. A keystone species has a fundamental role in influencing an ecosystem, helping maintain the structure within an ecological community. The abundance or lack of the keystone species will determine the abundance or lack of other species as well. It is common to use lions or wolves as examples of keystone species. If they disappear, certain animal populations that are usually hunted by them will prosper indiscriminately. That will drastically change the ecosystem, perhaps even leading it to its collapse. As we can see, the sea star describe in the passage is responsible for controlling the mussel population. The sea star is, therefore, a keystone species, preventing the overcrowding of mussels.

a factory opens that mass-produces light bulbs.

explanation:

not sure if that's an answer to your questions but this is an example! : )