Cervical vertebrae differ from other vertebrae in having -

With respect to the rib cage,explain the following: $(a)$ Bicephalic ribs,$(b)$ True ribs,$(c)$ Floating ribs.

Where are the Haversian canals found?

Match the following columns:

Column-$I$ (Vertebrae)	Column-$II$ (Number of bones)
$P$. Cervical	$I$. $1$
$Q$. Thoracic	$II$. $12$
$R$. Lumbar	$III$. $5$
$S$. Sacral	$IV$. $7$
$T$. Coccygeal	$V$. $(1)$ fused

Choose the wrongly matched option.

In humans,the knob-like projection of the second cervical vertebra helps in the rotational movement of the head. What is it called?