Earth science studies all natural sciences related to planet Earth. Earth consists of four spheres: biosphere, hydrosphere, atmosphere, and geosphere. Geology focuses on Earth's structure, substance, and processes
Radon was discovered in 1899 by Rutherford and Owens as a radioactive noble gas. It is colorless, odorless, and densest noble gas at room temperature. Radon has no stable isotopes, with 222Rn being the most stable (3.825 days)
Potassium-40 is a radioactive isotope with a half-life of 1.25 billion years. Makes up about 0.012% of total potassium in nature. Undergoes three types of radioactive decay
Sharks evolved from early chondrichthyans during Devonian Period. Modern sharks (selachimorphs) appeared in Early Jurassic (200 million years ago). Sharks belong to clade Selachimorpha, sister group to rays. More than 500 species split across thirteen orders
Natural science describes and predicts natural phenomena through empirical evidence. Science uses formal tools like mathematics and logic to explain nature. Modern science succeeded classical approaches to natural philosophy
Earthworms are soil-dwelling invertebrates belonging to phylum Annelida. They can reach lengths from 10 mm to 3 m in length. Have segmented body plan with setae on all segments. Live in moist soil, eating detritus and microorganisms