Oxygen is a compound , phosphorus and nitrogen , and reservoirs
Answer:
Hydrogen.
Explanation:
Hydrogen is the simplest chemical element that exists. The symbol for the chemical element Hydrogen is "H" and it is a colourless, tasteless, odorless, and highly flammable gas.
Hydrogen is a chemical element found in group (1) of the periodic table and as such it has one (1) electrons in its outermost shell. Therefore, Hydrogen has an atomic number of one (1) and a single valence electrons because it has only one proton and one electron in its nucleus.
Based on the octet rule which states that atoms of chemical elements gain, lose or share electrons so as to have eight (8) electrons in their valence shell. Therefore, atoms of chemical elements bond in order to attain the electronic configuration of a noble gas i.e a full valence shell which comprises of eight (8) electrons.
However, the chemical element "Hydrogen" is an exception to the octet rule because it is only able to hold a maximum of two (2) valence electrons in its outermost shell to become full.
<em>Hence, Hydrogen is an element which does not want to have eight valence electrons. </em>
Answer:
Having a standard system of measurments.
Explanation:
If they have one set of measurements used around the world, it is easier to communicate and work together.
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Answer& Explanation:
Angiosperm is more advanced due to the mechanism of protection it has since developed as opposed to its predecessor, gymnosperm. Angiosperms could be deemed the inventors of animal-mediated pollination or dispersal, whereas gymnosperms mostly depend on wind-mediated pollination (which is far more of a gamble than animal mediated).
1) Angiosperms seeds are enclosed in fruits, which increases the chances of dispersal by either wind, water, or animals. Animals can eat the fruit and disperse the seeds via feces or by brushing the fruit off of their fur coats new areas of the terrain.
2)The development of flowers. Flowers are especially important because depending on the flower it can attract a set species of animals in order for pollination to occur. That species of animal could only focus on those few flowers and would allow the female part of the flower to receive pollen (produced by the male part of the flower) from all over the place. This theory is also applicable to animal mediated fruit dispersal.
Discovery of structure of DNA by Franklin and Watson and Crick.
Explanation:
Rosalind Franklin was researching about DNA structure at the King’s College at London based on x-ray diffraction studies; while, Crick and Watson were researching on the same at the Cambridge University based on Linus Pauling discovery of proteins.
Once when Watson happen to listen to Franklin’s lecture upon DNA structure and how it depends on relative humidity of the air and other facts relating to DNA; he along with Crick made physical DNA models which became a big failure.
Later, Franklin found that a wet form of DNA with high humidity had a helix like structure. This point became the base of later discovery of Watson and Crick’s double helix model of DNA along with the discovery of DNA molecules being made up of double chain of nucleotides.
