Q 6.1 1. When two organisms compete, both have lower population growth rates than when they grow separately. Explain why. 3. The diversity of herbs along frequently disturbed roadsides is often high. What factors might account for that diversity?6.2 3. The common cold is caused by a viral parasite. New strains of the cold virus spread rapidly, especially in the wintertime. What factors allow new strains to spread so quickly? 6.3 1. What role does coevolution play in the development of mutualistic relationships in ecological communities? 6.4 1. What factors might influence trophic level efficiency?