A mass extinction event occurs when a species disappears far more quickly than it is replaced. This is typically understood as the loss of around 75% of all species over a "short" period of geological time, or fewer than 2.8 million years.
An enormous number of species were wiped out by a harsh, worldwide, swift, and selective event is mass extinction. According to marine fossils, at least 75% of all species are thought to have become extinct. The most recent mass extinction is the Cretaceous-Paleogene extinction event, which is also the only one that can be proven to have been caused by a significant asteroid impact. All non-avian dinosaur species, making up about 76 percent of all species on the earth, perished during mass extinction. The Chicxulub asteroid impact in what is now Mexico, which occurred 66 million years ago, caused an ecosystem collapse that resulted in the extinction of the dinosaurs and >75% of all land and sea species as well as the macroevolution of mammals.
Learn more about mass extinction
brainly.com/question/11872946
#SPJ4
<span>The stage at which all the cells show crossover chromosomes is meiotic prophase I. The crossover is the exchange of genetic material between homologous chromosomes. Homologous chromosomes are present in the meiosis I. Regarding the phase of meiosis I, it is expected that the crossover takes place in meiotic prophase I since homologous chromosomes pair up in the prophase.</span>
The correct answer is: E) cleavage furrow formation and cytokinesis
Cytochalasin B (cytos-cell and chalasis-relaxation) is a molecule which inhibit network formation by actin filaments by blocking monomer addition. As a result, itshortens actin filaments. This molecule is involved in cytoplasmic division where it blocks the formation of contractile microfilaments. One of the microfilament’s function includes cytokinesis and formation of cleavage furrow so these functions are affected by cytochalasin B.
Answer:
In evolutionary biology, abiogenesis, or informally the origin of life (OoL), is the natural process by which life has arisen from non-living matter, such as simple organic compounds. ... Many approaches to abiogenesis investigate how self-replicating molecules, or their components, came into existence.
Explanation:
<span>Orphan records are records whose foreign key value does not refer to a primary key value. Orphan records are very common in database relationships. The process used to remove and fix orphan records is called scrubbing the database.</span>