Within a single use of the scientific method, which of the following steps can only be performed after
data is collected?
a. controls and variables are chosen.
b. the initial experiment is designed.
c. the initial hypothesis is formed.
d. conclusions are drawn.

Within a single use of the scientific method, the step which would be performed after we collect data, would be the drawing of a conclusion out of the answers that you've presented - D.

It is usually the case that you first have to analyze the data after you've gather it and then you base your conclusions on it. This isn't, however, always the case. 

Answers
1). Eclipse
2). Circle
3). Sphere
4). Great circle
5). Triangle

Explanation
1). When a cylinder is bisected diagonally is forms a shaped that looks like an eclipse.
2). A cone has circular base. If it is cut such that it cross-section is parallel to the base then it will be a circle.
3). When you rotate a semi-circle about its axis it will form a sphere.
4). If a sphere is cut along its widest part it would form the great circle.
5). A triangle is formed when a cone is cut from the vertex to the centre of its base.