In hypogeal germination,which part of the embryo undergoes the greatest elongation?

Go through the following pairs and choose the correct pairs from the options given below:

$I$. Nerium	Sunken stomata	Lower epidermis of leaves to reduce loss of water
$II$. Calotropis	Non-succulent	Root cells with thickened cell walls
$III$. Peperomia	Leaf succulent	Leaf epidermal cell,store water
$IV$. Ammophila	Dicot	Curl their leaves to minimise loss of water
$V$. Tribulus	Ephemeral	Water is stored in stem

$A$: Development is the emergence of a multicellular organism from a single group of cells.
$R$: Development involves growth,differentiation,and morphogenesis.

Development = ........

Which of the following events occur during the process of development in plants?

Assertion: Senescence is the time when age-associated defects are manifested.
Reason: Certain genes may be undergoing sequential switching on and off during one's life.