Answer:
C. DNA
Explanation:
Prior to the discovery of DNA it was believed that proteins were responsible for carrying the hereditary information of the living organism. However, DNA was discovered in 1869 by German biochemist Johann Friedrich Miescher. His research focused on the white blood cells of pus, as these cells have large nuclei and are easy to isolate from the cytoplasm. The goal was to determine the chemical compounds in the nucleus of cells. The material for his research, pus, was easy to obtain from the bandages used for the wounds.
The biochemist has discovered a material of acidic nature composed of phosphorus and nitrogen. It was a compound, apparently made up of large molecules which it called nuclein.
In 1880 Albrecht Kossel demonstrated that the nuclein contained nitrogenous bases in its structure, hence they were rich in nitrogen as Miescher had shown.
In 1889, Miescher's pupil Richard Altmann proves the acidic nature by obtaining the high-purity nuclein, and called it nucleic acid, DNA.
b. Natural selection does not cause a species to change.
c. Natural selection is the only cause of changes in a species.
d. Natural selection usually causes a species to change gradually. please i beg help me 18 points if you help
Natural selection is a one of the basic mechanisms of evolution by which species adapt to their environment in order to increase their chance of survival and reproduction. It is the change in the characteristics that lead to survival. In natural selection, genotype variations that will increase the chance of survival and reproduction of some organism are preserved and will be inherited. So, natural selection will "select" those genotypes that help survival causing gradual change of species.
II) Electron density is focused on one element in the bond, generally resulting in the formation of a crystalline substance.
III) The greatest probability of finding the shared electrons is in the area of orbital overlap.
IV) The valence electrons involved in the bond are moving solely around the nucleus of the atom with the higher electron affinity.
es )
I and II
ll and I
I and III
I, III and IV
An substance for a crystalline is NaCl
Answer:
The statements which are indicative of a covalent bond are as follows -:
Explanation:
Among the given four statements, three statements are correct, the statement- "Electron density is focused on one element in the bond, generally resulting in the formation of a crystalline substance." is incorrect as In ionic bonds, crystalline formation takes place.
For a covalent bond, statements I) and III) are correct: the electron movement is focused between the bonded nuclei, and the greatest probability of finding shared electrons is in the area of orbital overlap.
In a covalent bond, the electrons move between the two atoms rather than being focused on one atom, which means statement I) is correct. Statement II) is typically characteristic of an ionic bond, not a covalent bond. Statement III) is also correct since the greatest probability of finding the shared electrons in a covalent bond is in the area of the orbital overlap. Statement IV) is incorrect because the electrons are not moving solely around one nucleus but are shared between the atoms.
Therefore, the covalent bonding characteristics are reflected in statements I and III, which indicates that electron movement is concentrated somewhere between the two bonded nuclei, and that the greatest probability of finding the shared electrons is in the area of orbital overlap.
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Polysaccharides play crucial roles in living things due to their diverse functions and properties. As complex carbohydrates made up of multiple sugar units, they serve as important sources of energy and structural components in organisms.
1. **Energy Storage:** One primary role of polysaccharides is to store energy for short-term and long-term use. Plants store excess glucose in the form of starch, while animals store it as glycogen in the liver and muscles.
2. **Structural Support:** Polysaccharides provide structural support in cell walls of plants, algae, and some bacteria. For example, cellulose forms the rigid cell walls of plant cells, giving them shape and support.
3. **Protection and Lubrication:** Some polysaccharides, like chitin found in the exoskeletons of insects and crustaceans, provide protection and structural support. Hyaluronic acid, a polysaccharide in connective tissues, acts as a lubricant and shock absorber.
4. **Cell Recognition:** Polysaccharides are also involved in cell recognition and signaling processes. They form part of cell surface markers and play essential roles in immune responses and cell communication.
Overall, polysaccharides are essential biomolecules that fulfill diverse functions, contributing to the proper functioning and structure of living organisms.
To know more about Polysaccharide:
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B. The RNA strand is produced within the cytoplasm.
C. The DNA strand is used as a template for which a complementary RNA strand can be produced.
D. The RNA strand forms a template by which DNA can be built
B. Alcohol
C. Water
D. Protein