The greater the amount of active transport carried out by a cell, the greater the amount of mitochondria would be found in the cell.
Active transport uses energy. Mitochondria undergoes aerobic respiration to release large amounts of energy. If the cell is found to be lacking in energy needed for active transport, the cell would adapt by synthesizing more mitochondrion to ensure that it's demand of energy is met.
Two criteria that would identify the three muscle tissues are myofibers and nuclei.
There are three types of muscles:
1. Skeletal-Contains many nuclei along the length of the muscle cell. The nuclei are displaced peripherally. The skeletal fibers are arranged parallel. The myofibril is composed of bands.
2. Smooth-This tissue contain spindle-shaped cells with a single central nucleus. Smooth muscle fibers are shorter than skeletal.
3. Cardiac-The fibers of cardiac muscle are not simply parallel. Cardiac muscle fibers are long cylindrical cells with one or two nuclei.
The correct answer is - the variable.
With the experiment, in the way that Dan had decided to perform it, the fertilizer is the variable, as in one of the parts with strawberries he uses fertilizer, while in the other part he doesn't uses fertilizer.
While this kind of experiment may give Dan some answers, and he might notice differences, still he would have to be more detailed in the experiment to see for sure if the fertilizer is the thing that makes some of the strawberries grow better than the others.
Dan should also put all of the strawberries at places that would receive the same amount of light, experience the same weather conditions, receive the same amount of water, and to be planted in a soil of the same quality. Only like this, after putting the fertilizer, Dan can now if it makes any changes or not.
