Which of the following properties is unique to echinoderms within higher invertebrates?

a time line cause it goes from 685 to 978

the answer is: trichonympha lives in the gut of termites and digests cellulose eaten by the termite.

this is an example of a symbiotic association of a protozoan with its mode of association.

hope i

-lavira: )

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]