D) The Earth was hit by a one or more objects from space 65 million years ago. The iridium layer shows an extraterrestrial cause for the extinction at the Cretaceous Tertiary boundary, discovered by the Alvarez family. The first discovery of this layer was in the Bavarian alps, in Lattengebirge. The Alverez family proposed that the extinction of the dinosaurs was due to a large meteor hitting the Earth at the end of the Cretaceous period, marking the KT boundary with this clay layer which has a high content of iridium. Iridium is not common on Earth, but is common in meteors.
Virions are physical entities containing nucleocapsid, capsid and sometime envelop. It exists extracellularly. Viruses are genetic material that occur intracellularly
Answer:
gravity
Explanation:
Gravity from Latin gravitas meaning weight for gravitation is a natural phenomenon by which all things with mass or energy including planets stars or galaxies and even light are brought toward or gravitate toward one another gravity gives way to physical objects
