Final answer:
In investigating how density-dependent limiting factors affect forest biodiversity and populations, appropriate research questions could be on the effects of overcrowding on deciduous trees, competition among deer, and disease spread in bird populations. These factors directly relate to biotic elements of an ecosystem and are influence by the population density, aligning with the investigation's focus. The correct answers are options A, C, and D.
Step-by-step explanation:
To plan and carry out an investigation on how limiting factors affect the biodiversity and populations in a forest ecosystem, with the focus on a density-dependent limiting factor, your lab group could develop research questions based on biotic factors which are influenced by the density of the population.
These factors include competition for resources, spread of disease, and the effects of overcrowding. As such, suitable questions from the options provided that correspond to density-dependent limiting factors are:
- A. What is the effect of overcrowding on the number of deciduous trees?
- C. What is the effect of competition on the population of deer?
- D. What is the effect of disease on the bird population?
Option A investigates how the access to resources such as space and nutrients can be limited when there is overcrowding, impacting the ability of deciduous trees to thrive. Option C explores how deer compete for food, water, and territory, and how this competition can limit their population growth. Lastly, option D focuses on how diseases can spread more rapidly within dense populations, affecting mortality and reproduction rates in birds.