Answer:
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.
If I would have to make a good guess, I would choose A.
Answer:
Presence of chlorophyll pigment in the leaves and cell walls were made of cellulose
Explanation:
The first plants that appeared on the land areas were comprised of the main component known as the cellulose that forms the cell wall of the plants and is responsible for making the various parts of plants such as branches, plant stems, and leaves, stronger and supportive.
In addition to this, the leaves of these primitive plants were comprised of green pigments known as chlorophyll that absorbs the sunlight and CO₂, and helps the plants in preparing the food for themselves as well as for the consumers, and also liberates oxygen (O₂) with it.
Thus, these are the two common characteristics that supported the idea that the primitive land plants had a relation with the green algae.