Answer and Explanation:
During the whole biota history, there occurred extinctions due to different reasons.
During the Cretaceous, which took place between 145-65 million years ago, there occurred a massive extinction that eliminated most of the species on the Earth. Many of the characteristic groups of this period were affected. Dinosaurs, Plesiosaurs, Ammonites, Tricodonts, Cycas, Gynkgos, Conifers, the recent angiosperms, birds, and mammals.
The extinction was caused by the volcanic eruptions, and the unusual fall of many different asteroids, which caused important changes on the Earth´s surface. The consequent climatic change was what ended affecting all the species directly. The extinction was gradual, although it occurred in a short geological lapse of time.
Answer:
Explanation:
Unicellular organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. All prokaryotes are unicellular and are classified into bacteria and archaea. Many eukaryotes are multicellular, but many are unicellular such as protozoa, unicellular algae, and unicellular fungi.
1. Protein Coat 2. Nucleic Acid
Transcription<span> proteins assemble at a hairpin loop formed by inverted repeats in the DNA template. RNA polymerase creates a nick in one of the DNA strands and begins to separate the nontemplate from the template.</span>
