Es un saco con paredes finas que rodea al feto durante el embarazo. El saco contiene líquido amniótico (líquido producido por el feto) y el amnios (membrana que cubre el lado fetal de la placenta), que proteje al feto de lesiones y ayuda a regular su temperatura.
Nematodes are wormlike organisms which can be seen with naked eye, live in water-filled pore spaces in the soil. Nematodes are in large number in the upper soil layers where organic matter, plant roots, and other resources are most abundant.
The functions of nematodes:
- Free-living nematodes decompose organic material into nutrients and cycled them in the soil by feeding on some bacteria and fungi.
- Nematodes help in distributing bacteria and fungi through the soil and along roots by carrying live and dormant microbes.
- They used as food for higher predators, soil microorthropodes.
- They eat disease-causing organisms, thus suppress their growth.
- They acts as potential bio- control agents.
Definition: "Copying of information from DNA to RNA which exit nucleus is known as transcription"
Explanation: Transcription is a vital process for living organisms, because it is a staring point for protein synthesis. It occurs inside the nucleus and is carried out by RNA polymerase enzyme. In eukaryotes RNA pol is of three types: these are RNA Pol 1, RNA Pol 2, and RNA Pol 3. In prokaryotes it is of only one type.
Steps in transcription: Transcription consists of three main steps
1. Initiation: In this step RNA pol attach to DNA template at 5 prime end in the promoter region to start the formation of complementary strand of RNA. In prokaryotes there is a region called
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Pribnow box, with the </span>consensus sequence<span> TATAAT present about 10 base pair away from site that serves as a transcription initiation. In eukaryotes the promoter region is more complex it contain activator and enhancer.
2. Strand elongation: </span><span>Once transcription is initiated, the DNA double helix unwinds and RNA polymerase reads the template strand, adding nucleotides to the 3′ end of the growing chain.
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3. Transcription Termination:
Terminator sequences are found close to the ends of non-coding sequences. Before termination polyadenylation occurs. <span>
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Answer:
The answer is the first option.
Explanation:
Farming emerged because being a nomad was no longer suitable for increasing population size. Farming allowed people to stay in one place and properly feed their families, which was a definite positive impact on population size.
Anton van Leeuwenhoek :-))