Answer:
Mass extinction is when biodiversity or species in a living habitat decreases to about three-fourths of its original number or to none. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. It occurs when the rate of extinction increases with respect to the rate of speciation. Mass extinctions are usually associated with organisms that are macroscopic rather than microscopic. Examples of mass extinctions are Permian extinction of marine species, and Cretaceous extinction of various species, including dinosaurs.
The correct answer is: [C]: "the rain" .
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Answer:
The correct answer will be option- synaptonemal complex.
Explanation:
The tetrad arrangement of the genetic material in an organism is mediated by a highly conserved structure known as the synaptonemal complex. The synaptonemal complex is formed during the prophase I of the meiosis I which attaches the chromatin of the homologous chromosomes.
The synaptonemal complex is a proteinaceous structure which is formed by the two lateral ladders like elements with a central portion composed of the central element. The chromatin gets attached to the lateral elements while the central a portion bridge space between the two ladders thus help in the formation of the tetrad.
Thus, option- synaptonemal complex is the correct answer.