The answer is C
Completing multiple trials during an experiment
The rest of the options are possibilities of how you can "mess up" and experiment, but if you run multiple trials doing everything right, for example, making sure all variables are controlled, using the right equipment, and making sure you cover all possible variables. If you make sure you do multiple trials and you do them right, you get successful results.
So the answer is C
I hope this was helpful :)
Goodluck!!
1. Filament
2. Anther
3. Petal
4. Stigma
5. Style
6. Ovary
7. Sepals
8. Stem
A difference between coelom and Pseudocoelom is that the gut of a pseudocoelom is surrounded by the endoderm, and the gut of a coelomate is surrounded by the ectoderm. So your answer is D.