Answer:
Angle of light source
Explanation:
Independent variable is the variable that the experimenter changes or manipulates in an experiment in order to bring about a measurable response, which is the dependent variable.
In this question, a student wants to investigate the effects of phototropism in bean plants. She places a light source directly above one plant, at a forty-five degree angle to another, and at a ninety-degree angle from the third. This shows that the variable being manipulated (independent variable) is the ANGLE OF THE LIGHT SOURCE.
If you have both parents with long ears and some of the offsprings have short ears, you can say both parents are heterozygous for this. Both have a dominant (long ear), and a recessive allele (short ear).
To prove this, you can draw a Punnett square, and you'll see the probabilities of the offsprings.
