Answer: D
Explanation:
Could RNA have provided a template for DNA assembly, thereby enabling a more stable molecule that is replicated more accurately?
The flexible nature of a cell membrane results from its PHOSPHOLIPIDS.
Cell membrane is made up of four different types of molecules; namely phospholipids, cholesterol, proteins, and carbohydrates. <span>Its flexibility is from phospholipids because phospholipids are made up of two layers; one layer is hydrophilic and the other is hydrophobic. Just like a vegetable oil, the hydrophobic layer of the phospholipid bilayer does not like water and is able to move sideways with in the cell membrane to avoid contact with water. </span>
Answer: Option (D) is the correct answer.
Explanation:
Non-metals are electron deficient in nature so, in order to complete their octet they need to gain electrons from metals or electron rich atoms.
Whereas metals are electron rich in nature so, in order to gain stability metals lose their valence electrons.
For example, atomic number of potassium is 19 and its electronic distribution is 2, 8, 8, 1. Whereas atomic number of chlorine is 17 and its electronic distribution is 2, 8, 7.
Therefore, sodium in order to gain stability will lose its valence electron to chlorine atom. Hence, an ionic bond will be formed resulting in the formation of KCl.
Thus, we can conclude that non-metals seek to gain electrons to have full outermost shells, while metals seek to lose electrons to have full outermost shells.
Answer:
D. People allow only organisms with certain traits to reproduce.
The limbic system is a set of brain structures, not a separate system which is located on both sides of the thalamus and it includes structures from the telencephalon, diencephalon, and mesencephalon. This system is involved in feeling the emotions such as joy and happiness. For example, nucleus accumbens is part of the limbic system and it is involved in reward and pleasure that can make happiness.
Besides that, the precuneus (located in front of the upper portion of the occipital lobe) is involved in feeling happiness. Scientists have shown that there is a positive correlation between the volume of grey matter in the right precuneus and the subject's subjective happiness score.
