$A$ non-succulent xerophyte with thick leathery leaves having a white sticky waxy coating is:

Given below are two statements $:$
Statement $- I :$ The arrangement of ovules within the ovary is known as aestivation.
Statement $- II :$ The mode of arrangement of sepals and petals in floral bud with respect to the other members of the same whorl is known as placentation.
In the light of the above statements,choose the correct answer from the options given below $:$

Raphides are crystals of

Definitions / Explanation :
$(i)$ Phylloclade
$(ii)$ Aestivation

$A$: Cattle or goats never graze on $Calotropis$.
$R$: Thorns are present as a morphological means of defence.

Commercially useful surface fibers are obtained from which of the following?