$Acacia arabica$ is a

In syngynia,the flowers are

$S :$ In Catharanthus roseus,the number of carpels is two.
$R :$ Catharanthus roseus is an example of a bicarpellary condition.

Aestivation of petals in the flower of cotton is correctly shown in

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

Given below are two statements.
Statement-$I$: The arrangement of ovules within the ovary is known as placentation.
Statement-$II$: If a fruit is formed by fertilization of the ovary,it is called a parthenocarpic fruit.
Choose the correct answer from the options given below.