In an experiment, Dr. Travis examined the effects of calcium intake on osteoporosis, a condition that causes an increased risk of bone fractures. The amount of calcium variable. The risk of bone fractures . 1. A reliable
An independent
A dependent

2. Can be changed by the participants
Can be changed by the researcher
Could change with calcium intake

Part 1.  The amount of calcium is independent variable.

Explanation:

An independent variable is a variable in an experiment which is changed to see its effects on dependent variable.

In this experiment, to know about the causes of osteoporosis, the Ca level in blood or calcium intake in changed.

So the concentration of calcium will be independent variable.

Part 2.

The risk of bone fractures is could be changed with calcium.

Explanation:

In this experiment osteoporosis or risk of bone fracture is dependent variable.

Dependent variable are results of experiment which can be changed by independent variable.

As in experiment, Calcium concentration is independent variable.

So the risk of osteoporosis depends can change with calcium.