In humans,the ....... teeth help in cutting.

Assertion $A$: Mammals are heterodont.
Reason $R$: In mammals,permanent teeth replace temporary milk teeth.

Match the Column $I$ with Column $II$,with reference to human beings:

Column $I$ (Part of the alimentary canal)	Column $II$ (Length)
$i$. Duodenum	$b$. $26 \ cm$
$ii$. Jejunum	$c$. $2.5 \ m$
$iii$. Ileum	$d$. $3.5 \ m$
$iv$. Large intestine	$a$. $1.5 \ m$

Match the names of glands listed under column $-I$ with the location given under column $-II$, choose the answer which gives correct combination of the alphabets of the two columns.

Column $-I$ (Glands)	Column $-II$ (Location)
$(A)$ Crypts of Lieberkuhn	$(p)$ Loop of duodenum
$(B)$ Pancreas	$(q)$ Stomach
$(C)$ Adrenal gland	$(r)$ Intestine
$(D)$ Gastric gland	$(s)$ Kidney

The outermost layer of an alimentary canal is known as

Define / Explain the following terms:
$(1)$ Diphyodont
$(2)$ Thecodont