Answer:
Covalent bonds are the types of Bond which is formed by sharing of an electron between two atoms of same element or two different elements. The bond which is formed by the completely lost or gained of an atom is known as ionic bond.
Explanation:
The most common example of covalent bond is formed from carbon atom. The valence of carbon atom is 4. Therefore, it is very hard to gain or lose an electron from the carbon atom. Therefore, the carbon tends to share the electron instead of completely losing or gaining the electron.
Ionic bond is very common and it can be formed by many elements from the periodic table. Ionic bond is more stable and stronger when compared to the covalent bond in nature.
Answer:
this phenomenon is a natural consequence of evolutionary processes and continental drift
Explanation:
Marsupials are mammals in which newborn offspring are carried in a pouch of the female (mother) body. On the other hand, placentals are mammals that complete embryo development in the mother's body, in the placenta. All the extant marsupials are endemic to Australia and the Americas. It has been shown that marsupials diverged (evolved) in South America, Australia and Antarctica when these landmasses were joined. In Australia, marsupials evolved to fit an ecological niche, which can be attributed to geographic isolation due to continental drift, while placental mammals are relatively recent and more scarce (mainly bats and rodents) within this region.
Answer:
Aldehyde Dehydrogenase 2 (ALDH2) is an enzyme required to eliminate toxins such as acetaldehyde and alcohol, thereby mutations in this protein may be associated with the Alcohol flush syndrome (AFS)
Explanation:
ALDH2 is a protein required for ATP generation by catalyzing the oxidation of aldehydes to carboxylic acids (i.e., oxidation of NADH to NAD+). Mutations in the ALDH2 gene have been associated with the inactive form of this enzyme, and this specific mutation at position 487 alters its enzymatic activity associated with the metabolism of acetaldehyde and alcohol. This amino acid substitution may lead to the active site-directed inactivation of the enzyme.
The organelles that scientists believed that it originated by symbiotic relationships between primitive eukaryotes and certain prokaryotes is known as chloroplast. Chloroplast contain chlorophyll which capture energy from sunlight that is used in photosynthesis .This energy is converted to ATP and NADPH
