A) DNA fulfils all three conditions:
<span>(1) copy itself precisely - in the process of replication, DNA copies itself and two molecules of DNA are formed. This process is very precise thanks to the great number of proteins involved in these process that prevents error occurring and proteins that can fix the error if it occurs.
(2) be stable but able to be changed - DNA is very stable molecule otherwise, it cannot be a genetic material. However, its chains can separate in a short length so the translational machinery can attach to it and the process of transcription can occur. Also, in crossing over, during meiosis, </span>the exchange of genetic material occurs and chromosomes change a bit.<span>
(3) be complex enough to determine the organism’s phenotype - it contains a number of genes responsible for different traits. All of this results in the </span>organism’s phenotype.
B) DNA copies itself. <span>Meselson and Stahl conducted the experiments on DNA replication in which they used </span>E. coli<span> bacteria as a model system. After they labelled all bacteria's DNA with heavy 15N by using medium with heavy 15N, they switched bacteria to medium with light 14N. After several generations, all bacteria's DNA was labelled with light 14N. This experiment evidenced that the self-replication of DNA is semi-conservative process.</span>
Answer:
True
Explanation:
The sympathetic autonomic nervous system activates the body for hormonal or neuronal responses also known as fight- or - flight response, For example during an fire emergency and there is a need to run. The response occurs primarily by via impulses transmitted through the sympathetic nervous system, and also secondarily through catecholamines secreted from the adrenal medulla.
Although the sympathetic autonomic nervous system is activated in stressful conditions, it needs to be constantly active even at a basal level to maintain homeostasis.
Answer:
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Explanation:
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