Answer:
In 1884, Hans Christian Gram described a method of staining bacterial cells while not staining surrounding animal tissues. However, he thought that the staining method he developed was faulty because not all bacteria stained. ... Not all bacteria stained because some have walls that prevents the staining.
Answer:
<em><u>D. The first flowering plants were introduced toward the end of the Mesozoic era.</u></em>
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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>
In ecology, the competitive exclusion principle, sometimes referred to as Gause's law of competitive exclusion or just Gause's law, is a proposition that states that two species competing for the same resource cannot coexist at constant population values, if other ecological factors remain constant.
Answer:
the genetic code is universal.
Explanation: