Editor's Note: While we can't endorse what X has become, we can bring you the worthwhile moments that still exist there, curated and free of the surrounding chaos. American politics — well, frankly, ...

Genetic variation describes naturally occurring genetic differences among individuals of the same species. This variation permits flexibility and survival of a population in the face of changing ...

In ecology, biotic and abiotic factors encompass all the living and non-living parts of an ecosystem. Biotic factors pertain to living organisms and their relationships. Abiotic factors are the ...

S. D. Albon, T. H. Clutton-Brock and F. E. Guinness (1) We investigated cohort differences in survival and reproductive success of female red deer in an increasing population on the Isle of Rhum, ...

The Public Transport Access Calculator (PtAC) is an open source tool for assessing access to public transport. It enables the assessment and monitoring of the United Nations Sustainable Urban ...

Radiocarbon dating, or carbon-14 dating, is a scientific method that can accurately determine the age of organic materials as old as approximately 60,000 years. First developed in the late 1940s at ...

All organisms in an ecosystem depend on each other. Food chains show the flow of energy from one organism to another. Food chains show the feeding relationships between organisms. Food webs show how ...

The Co-operative Republic of Guyana is a small, sparsely populated South American country with abundant natural resources. Although geographically situated in South America, the country is culturally ...