<u>Answer:</u>
In ecology, catastrophes permanently alter the physical structure of the existing environment.
<u>Explanation:</u>
- The ecological disturbances include flood, strom, plague, fires, earthquakes, tsunami, volcanic eruptions, climatic change and impact of humans on the environment like deforestation ,nuclear testing etc.
- These factors can have a visible impact on the structure of the earth and permanently alter the environment.
- The visible effects of these disturbances are global warming, extinction of selective species, change in the course of rivers, submergence of coastal areas, sudden movement of the tectonic plates and formation of sudden cracks on the earth's crust.
d. Eras are divided into periods; periods are divided into epochs.
The geologic time is divided from the largest defined unit of time called supereon, which is composed of eons. Eons are further subdivided into eras, periods, epochs and the smallest unit of time - ages.
Answer: Viruses, although not living things, do show some characteristics that they are living. Because they can't reproduce by themselves (without a host), viruses are not considered living. They are made of proteins and glycoproteins like cells are. They contain genetic information needed to produce more viruses in the form of DNA or RNA.
They are acellular, that is, they contain no cytoplasm or cellular organelles. They carry out no metabolism on their own and must replicate using the host cell's metabolic machinery.
I hope this helps, the esophagus is a muscular tube connecting the throat (pharynx) with the stomach. The esophagus is about 8 inches long, and is lined by moist pink tissue called mucosa. The esophagus runs behind me he windpipe (trachea) and heart, and in front of the spine.
Answer:
look there are 2 types of cells 1 is animal cell and 2 is plant cell that makes the difference between the both of them