<h3><u>Answer and explanation;</u></h3>
- DNA is a double stranded molecule. Covalent and hydrogen bonds pray important roles in the functioning of DNA molecules.
- <em><u>Covalent bonds occur within each linear strand and strongly bond the nucleotide bases, sugars, and phosphate groups occurring both within each component and between components.</u></em>
- <em><u> Hydrogen bonds occur between the two strands and involve a base from one strand with a base from the second in complementary pairing.</u></em>
- Hydrogen bonds helps the complementary base pairs in DNA; guanine with cytosine and adenine with thymine to connect to one another. The hydrogen bonds between these complementary pairs helps keep the two strands of DNA helix together.
The axon, or nerve fiber, is an extension of the neuron that drives the electrical signal from the cell body to the synaptic zones. Along the axon, this signal consists of action potentials.
The other extensions of the neuron are the dendrites that lead the signal from the synapses to the cell body (to be then driven to the axon). The neurons most often have a single axon and several dendrites (the influx can come from several directions, or several dendrites, but always converge towards the axon).
Answer:
According to Darwin's theory of evolution, new species evolved as a result of natural selection.
Explanation:
- Darwin proposed that speciation could readily occur through the prolonged action of Natural selection.
- Natural selection allows the 'survival of the fittest' i.e. a more fit organism will have a better chance of survival than the less fit one.
- The result of Natural selection could be positive,negative or balancing.
- Evolutionary process in which the genetic changes confer a higher fitness to increase frequency of the organism over time in population is called positive selection.
- Evolutionary process in which genetic changes decreases the organism's fitness resulting in its disappearance from the population is called Negative selection.
- It may happen that a mutation benefits hetero-zygotes but not homo-zygotes and alleles maintain a intermediate frequency in population.This evolutionary process is called balancing selection.
Rhenium is the very dangerous (hazard wise) it should be handled carefully and you should understand that THIS should not be taken lightly I hope this helps!:)
