Note when doing the practical questions, creating models, keep in mind that there is often no one right way of making a model. Hence, you might create the model in a different way, such as that suggested here:

1. Features are our way into 3D in SOLIDWORKS. We usually use features directly after sketching to go from 2D sketches to 3D models. In order, features are commonly used after sketches. They are also mostly built based on sketches.
2. The features, extruded boss and cut, enable us to add or remove materials by extending the sketch perpendicular to the sketch plane. 
3. Fillets and chamfers enable us to remove sharp edges or corners from our models and replace them with fillets or chamfers.
4. The revolved cut and revolved boss features enable us to add or remove materials by revolving a sketch around a revolution axis of our choosing. 
5. First, make sure your measurements system is set to IPS. To create the shape, we can use the features extruded boss, extruded cut, and fillet. The two steps can be created with two extruded bosses. Then, the hole can be made with an extruded cut. The fillet feature can be applied to round the top edges with a 0.2 inches radius. 
6. First, make sure your measurement system is set to MMGS. For this, we can use the revolved boss feature to create the sphere. We can start with a sketch of the letter D. Then, select the straight edge as the axis of revolution, as shown in the following diagram:

7. First, make sure your measurements system is set to MMGS. Then, we can start by creating a profile in the shape of an ellipse, as shown in the following diagram:

We can then apply the feature revolved boss by 270 degrees to create the general shape. The circular hole shares the same center with the ellipse which we can add in a different sketch and use the feature revolved cut. An alternative way is to sketch both the ellipse and the hole together in one sketch, and then apply the feature revolved boss. 

8. First, make sure your measurement system is set to IPS. Then, we can create a rectangular base layer. After that, we can draw a circle and apply linear patterns to generate a total of 15 circles. Then, we can use extruded boss to extrude the pattern generated, as in the following diagram: 

The following screenshot highlights the PropertyManager for the Linear Pattern used in this exercise: