The four postulates of the natural selection include.
1. individuals possessing particular traits are have higher likelihood of surviving and reproducing.
2. different individuals in a population have different traits
3.reproductive and survival rate vary with individuals in a given population.
4. some trait differences are inheritable.
The answer is B. Geology has shown a thin layer of iridium (a rare mineral on earth but found on asteroids and meteors) in the rock layers between the Cretaceous and Paleogene periods. Below this layer are numerous fossils of pterosaurs and dinosaurs, but above the layer are drastically few. The aftermath of asteroid impact is believed to have smothered most vegetation from earth which dinosaurs depended on as a source of food.
I think Earth’s atmosphere plus atmosphere. So, 23+48=71. So, the answer is A
Answer:
The Law of Conservation of Mass is defined and explained using examples of reacting mass calculations using the law are fully explained with worked out examples using the balanced symbol equation. The method involves reacting masses deduced from the balanced symbol equation.
Explanation:
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Brainliest please
Answer:
There are many points at which eukaryotic gene expression can be controlled, through pretranscriptional control, transcriptional control, and posttranscriptional control
Explanation:
The pretranscriptional control determines the accessibility of chromatin to the transcription machinery. It is affected by supercoiling and methylation. It is also known as epigenetic regulation, and it does not depend on the sequence but on the conformation of the DNA.
While transcriptional control determines the frequency and / or speed of transcription initiation through the accessibility of the start sites, the availability of transcription factors and the effectiveness of promoters.
The post-transcriptional control is the one that is exercised once the transcript has finished synthesizing. It can be of several types:
• Maturation control: As the RNA adjustment can be made.
• Transport control: Most RNA has to go out to the cytoplasm to perform its function. For this they have to cross the pores of the nuclear membrane, where you can select the RNAs that will be transported and those that will not.
• Stability control: The half-life of RNA can be regulated by the expression of RNAs or mRNA stabilizing proteins in the cytoplasm.
• Translational control: It is exercised on the frequency with which the mRNAs begin to be translated. It can also affect the frequency with which proteins mature and the availability of enzymatic effectors.
