The best response that describes Ruby gathering enough evidence to support a scientific explanation concerning plant growth rates is:
Ruby measures the heights of several species A, B, C, and D plants for a week under the same conditions and finds journal articles that describe the growth rates of each species.
This response is the most scientifically rigorous because it involves systematic measurement of the heights of various species under identical conditions, which allows for a fair comparison of growth rates. Additionally, seeking out journal articles provides evidence from existing research, strengthening the reliability of her findings.