Scientists used case studies to help them determine that the right side of the body was connected to the left of the brain and vice versa. A case study is a process or record of research into the development of a particular person, group or situation of a given period of time.
The correct answer is option (A) Variation in the strawberry plants.
When the effect of fertilizer on the growth of two strawberry plants is tested, unavoidable source of experimental error is the variation in the strawberry plants. Variation refers to the deviation or differences from the normal plant which can be due to genetic variation. It is due to change in the DNA sequence. If any one of the two plants being tested show variation, the rate of metabolism differs and changes the growth pattern of the plant. The rate of absorption of water and nutrients is effected which brings change in the growth of the plant and causes an error in the experiment and the result.
The type of mutation seen is germline mutation
