An endoskeleton of calcified cartilage
These abnormalities occur in the serotonin system which reduces and/or inhibits control in their movement. This disruption of the neurotransmitter causes them to act maladaptively. Thank you for your question. Please don't hesitate to ask in Brainly your queries.
they are so unique and seen often
The answer is alveolates. The sac-like structures under their plasma membrane are called alveoli. The alveoli provide support to the plasma membrane. Examples of groups of alveolates are ciliates, such as Paramecium, dinoflagellates, apicomplexa, and foraminifera. They lie under the phylum, Ciliophora.
