The best statement 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 approach ensures that Ruby collects comparative data under controlled conditions, allowing for a valid assessment of growth rates among the different species. Additionally, consulting journal articles provides relevant scientific background and supports her findings with established research.