A circular sector or circle sector (symbol:⌔), is the portion of a disk enclosed by two radii and an arc, where the smaller area is known as the minor sector and the larger area is the major sector. In the diagram, θ is the central angle in radians, r is the radius of the circle, and L is the arc length of the minor sector.

Drawing figures: 2 Marks
Reason: 1 Mark
In ∠ABC we use two lines AB and BC to make ∠B whereas in ∠BAC we use lines BA and AC to make angle ∠A.

Each Point: 1 Mark
1. An infinite number of lines can pass through one given point.

2. Only one line can pass through two given points. 

Definition: 1 Mark
Solution: 1 Mark
A line segment is a piece, or part, of a line in geometry.

A line segment is represented by endpoints on each end of the line segment.

A line in geometry is represented by a line with arrows at each end.

A line segment and a line are different because a line goes on forever while a line segment has a distinct beginning and end.

Explanation: 1 Mark
Solution: 1 Mark
Naming of Rays: 1 Mark
Common Ray: 1 Mark
In $\angle$ ABC and $\angle$ CBD, BC is a common arm. So, $\angle$ ABC and $\angle$ CBD form a linear pair.
Hence, $\angle$ ABC + $\angle$ CBD = $\angle$ ABD.
The various rays in the above figure are BA, BC, BD.
The two angles that share a common ray are $\angle$ABC and $\angle$CBD.

Each option: 0.5 Marks
(a)  $\angle$ ABD   
(b)   $\angle$ RTS 
(c)  $\angle$ ACD and  $\angle$ ACB
(d)   $\angle$ RTW and  $\angle$ RTS
(e)   $\angle$ AED,  $\angle$ AEB,  $\angle$ BEC and  $\angle$ DEC
 (f)   $\angle$ AEC
(g)   $\angle$ ACD
(h)   $\angle$ AKO, $\angle$ AKP,  $\angle$ BKO,  $\angle$ BKP

Each option: 1 Mark
(a)  CP and AB are two chords of the circle.

(b)  OP, OC, OA and OB are all radii of the circle.

(c)  CP is a chord of the circle, which is not a diameter.
(d)