Answer:
The cell cycle is controlled by many cell cycle control factors, namely cyclins, cyclin-dependent kinases (Cdks) and cyclin-dependent kinase inhibitors (CKIs). Cyclins and Cdks, which are positive regulators of the cell cycle, activate cell cycle factors that are essential for the start of the next cell cycle phase.
Explanation:
Listen to pronunciation. (sel-SY-kul REH-gyoo-LAY-shun) Any process that controls the series of events by which a cell goes through the cell cycle. During the cell cycle, a cell makes a copy of its DNA and other contents, and divides in two.
Earth's history. In the worst one, 250 million years ago, 96 percent of marine species and 70 percent of land species died off. It took millions of years to recover.
Answer:
<em><u>D. The first flowering plants were introduced toward the end of the Mesozoic era.</u></em>
<em><u /></em>
Explanation:
Following the Paleozoic Era, the Mesozoic Era or <em>Age of Conifers</em> began approximately 250 million years ago. This major geological era brought about the ancestors of many of the plant and animal groups still in existence today.
The Mesozoic era is marked by 3 divisions:
- the Triassic Period,
- the Jurassic Period,
- and the Cretaceous Period.
Animals and plants slowly recovered after the mass extinction in the Permian-Triassic extinction that led to the eradication of most aquatic marine species. They evolved to exploit varying niches in their environment, leading to a boom in terrestrial animals. Over time the planet's increasingly warm climate, abundant in atmospheric oxygen and carbon dioxide, contributed to the growth of diverse megaflora, that rapidly dominated the planet's terrestrial biosphere.
By the end of the <em>Mesozoic Era</em>, in the Cretaceous period, flowering plants (angiosperms) largely replaced the dominant seed ferns of the <em>Triassic</em>, and the conifers, cycads and gymnosperms of the <em>Jurassic</em>.
<em>Varied dispersal mechanisms in angiosperms co-evolved with the evolution of certain types of fauna. Plants used animal life, including herbivorous reptiles and early mammal-like species to disperse large seeds.</em>
Cold ocean water flows from the north pole towards south and affects the climate locations near the Atlantic Ocean.