Answer:
1) B
2) A
3) A
4) D
Explanation:
An atom is neutral because it contains an equal number of protons and electrons. Though the atom actually contains neutrons, this reason does not explain the electrical neutrality of the atom.
The L shell actually contains eight electrons because the maximum number of electrons accommodated in each shell is given by 2n^2 where n is the principal quantum number. Since the L-shell corresponds to n=2 then the reason is the correct explanation of the assertion.
The valency of atoms is determined by the number of electrons in the outermost shell of the atom. Remember that atoms having a filed valence shell(eight electrons in the outermost shell) have a valency of zero. Hence the noble gases possess a zero valency. Thus the reason is the correct explanation of the assertion.
Nitrogen forms its ion by electron gain and not by electron loss because nitrogen forms an anion. This anion is formed by a gain of three electrons. The assertion is false but the reason is true.
The answer is; D
Archaebacteria are early life forms on earth. They utilized the process of chemosynthesis to make organic molecules from inorganic molecules and for energy. The word archae means ‘ancient’ life forms. These single-celled organisms evolved around sulfur-rich environments of the hydrothermal vents.
The hollow<span> part of a </span>bird bone<span> isn't wasted space. In some </span>bones<span>, the </span>hollow<span> cavities contain extensions of the air sacs from the lungs. These air sacs help the </span>bird<span> to get the oxygen it needs to fly quickly and easily.</span>
Slightly greater, but not too much, or the cell will rupture (cytolysis).
The correct statement is liver cells possess transcriptional activators that are different from those of lens cells.
<h3>What are Transcriptional activators?</h3>
Transcriptional activators are specific protein sequences capable of activating gene expression.
These transcription factors (transcriptional activators) act to regulate gene expression in target cells.
Transcriptional activators are factors that enable the expression of certain genes in particular cell types.
Learn more about Transcriptional activators here:
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