All forms of RNA are intermediate molecules that are fabricated within DNA to perform cellular functions.
mRNA - messenger RNA carries selected portions of DNA used to fabricate polypeptides used to fabricate amino acids for protein.
tRNA - transfer RNA is comprised of select genetic code and transfers amino acids to ribosomes for assembly
rRNA - ribosomal RNA is comprised of select genetic code and makes the ribosomes
RNA is highly mutatable, highly reactive, non-reproductive, and highly specialized metabolically, and consequently totally unsuitable for consideration of any pre-DNA senario being posited for the origin of life.
<h3><u>
The following events are identified as chemical weathering:</u></h3>
- The minerals in a marble statue react with water to form acids and pores in the structure.
- The rocks in a region are streaked orange after being exposed to repeated rains.
<em><u>Reason: </u></em>
When the weathering process occurs due to <em>chemical reaction</em>, then it is considered as chemical weathering.
In <em>the first case</em>, minerals of marble statue are <em>reacting</em> with water to cause weathering. In the <em>second case</em>, due to the <em>acidificaion reaction</em>, the change of the color has happened after exposure to the repeated rains.
<h3><u>
The following events are identified as Mechanical weathering:</u></h3>
- A piece of rock crumbles after being constantly thrashed by strong waves.
- Industrial runoff forms cracks in a rocky structure in its path.
<em><u>Reason:</u></em>
When the rock is broken into simple pieces <em>without any chemical reaction </em>it is considered as mechanical weathering.
In the <em>first cause</em>, due to the <em>abrasion</em> caused by the strong waves, weathering has happened, in the <em>second case</em> industrial run off may be of varying temperature and thus may cause <em>heating or cooling</em> of the rock and causes weathering.
Answer:
<em><u>The water in lakes comes from rain, snow, melting ice, streams, and groundwater seepage. If water leaves a lake by a river or other outlet, it is said to be open. All freshwater lakes are open. If water only leaves a lake by evaporation, the lake is closed.</u></em>
There are small tubes that connect all parts of a plant or a tree with the root. The root then applies root pressure to the nutrients and the nutrients and the water are pumped towards the upper parts through these small tubes.
