Joints have two degrees of bending freedomarthropods
The joints of some arthropods have two degrees of bending freedom (up-down and left-right) thanks to two 1-degree bending joints found at right angles to each other.
Matrix stiffens connective tissuesponges
The connective tissue of sponges is a matrix stiffened by embedded spicules.
Skeleton provides supportsponges
The spicular skeleton of sponges provides structural support in the form of dispersed struts.