Weathering: Weathering occurs in situ (on site, with little or no movement), and should not be confused with erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity. Weathering processes are divided into physical and chemical weathering.
erosion: Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind or gravity. Mechanical weathering physically breaks up rock. One example is called frost action or frost shattering. ... The sediment is dropped, or deposited, in landforms.
deposition: Deposition is the processes where material being transported by a river is deposited. Deposition occurs when a river loses energy. This can be when a river enters a shallow area (this coud be when it floods and comes into contact with the flood plain) or towards its mouth where it meets another body of water.
28. <u>Answer</u>: All mutations do not affect the organisms due to the following reasons:-
1. The DNA consists of both coding and non coding regions. The coding regions are known as exons and non coding regions are called as introns. The <em>non coding regions </em>do not make up the protein. Thus, if the mutations occur in non coding regions they do not affect the organism.
2. There are some mutations that result in the change of the codon but the new codon formed codes for the same amino as the previous one. This is possible because of the degeneracy of genetic code. For eg, AAA codes for lysine, however if the mutation changes this code to AAU then this also codes for lysine. Such mutations are called as <em>silent</em> mutations.
3. There are some mutations which result in the change in amino acid however the new amino acid formed is similar to the previous one in its properties for e.g leucine and isoleucine. Such mutations are called as <em>neutral</em> mutations and they do not affect the organism
29. <u>Answer</u>: 1. The process of mitosis results in the formation of <em>two diploid cells</em> whereas meiosis results in the formation of <em>4 haploid cells.</em>
2. The process of mitosis takes place to produce copies of the <em>body cells </em>whereas the process of meiosis takes place to produce the <em>gametes</em>.
<u>Explanation</u>:-
- <u>Mitosis</u> is a process in which a cell undergoes a single round of division to produce two identical copies of itself . It occurs in 4 phases Prophase, metaphase, anaphase and telophase. This process occurs in the body cells.
- <u>Meiosis</u> is a process in which a cell undergoes two rounds of cell division to produce 4 copies of haploid cells from a single diploid cell. This process takes place for the formation of gametes.
29. <u>Answer</u>:
<em>Pros</em>
1. Genetic engineering helps us to tackle several diseases. There are many diseases which are caused due to genetic mutations. Genetic engineering helps us to rectify these mutations and hence combat such diseases.
2. Genetic engineering helps us to produce new foods which can withstand adverse conditions such as high/low temperatures, low rainfall, are disease and pest resistant etc. This, genetic engineering helps to significantly improve crop production.
<em>Cons</em>
1. Genetic engineering leads to a decrease in genetic diversity.
2. It can lead to a decrease in the nutritional value of food as genetic engineering often causes an accelerated growth of animals and hence, the nutritional valie of poultry foods is compromised.
Answer:
genetic recombination
Explanation:
Bacteria and other harmful organisms like viruses infect people rapidly with genetic recombination.
Hope it helps.
Answer:
In the group of terms, the exception to abiotic factors is bacteria (option b).
Explanation:
Abiotic factors correspond to the elements of an ecosystem that are not considered alive, such as soil, wind, temperature, pH, among others.
All living beings in an ecosystem are biotic elements, including microorganisms such as bacteria. The dynamics of living beings influence the ecosystem, just as abiotic factors influence both the biotic elements and the development of the ecosystem.
The landscape in which limestone is eroded to form deep valleys and cavers are called Karst landscape or karst topography. This kind of development start occuring whenever the acidic water starts breaking down the bedrocks near the cracks. As the bedrock starts breaking down slowly, the cracks start to open up creating bigger holes. with passage of time the holes will become big enough to create an underground drainage system for the surface water to flow and form underneath. If the water is unable to flow out and becomes stagnant, then the Karst will start getting bigger.
