In frog, the vertebra with an anterior convex surface (i.e., double convexties) is
atlas
urostyle
8th vertebra
9th vertebra
What is left when bath sponges dries up
Spicules
Spongin fibres
Tentacles
Holdfast
B.
Spongin fibres
Euspongia is called bath spongia. The sponge are classified on the basis of skeleton which is made up of spongin fibere. After the bath sponge dries only the skeleton is left.
The first phylogenetic system of plant classification was proposed by
Engler
Engler and Prantl
Eichler
Wetlstein