State TWO factors, regarding the females, that should have beenkept constant during the investigation

Without knowing the context or the specific investigation being referred to, it's difficult to provide an accurate answer. However, in general, when conducting an investigation involving females, two factors that should typically be kept constant could be:

1. Age: The age of the females should be kept constant to ensure that any changes or results are not due to age differences. Age can affect many biological and physiological processes, so it's important to control this variable.

2. Health Status: The health status of the females should also be kept constant. This includes any pre-existing conditions or diseases. Health status can significantly affect the results of an investigation, so it's crucial to control this variable as well.

Please provide more context or details about the investigation for a more accurate answer.