Answer:
Option D is the correct answer
Explanation:
There are three hydrogen bonds formed between Guanine and Cytosine base.
The first hydrogen bond is formed between the oxygen atom on Carbon-6 (C-6) of guanine, and one of the hydrogen atoms attached to the Nitrogen atom (i.e the one of the hydrogen atoms in the amino group) on the Carbon-4 (C-4)of the cytosine base.
The second hydrogen bond is formed between the hydrogen atom on Nitrogen-1 (N-1) of the guanine base and Nitrogen-3 (N-3) of the cytosine base.
The third hydrogen bond exist between one of the hydrogen atoms in the amino group attached to the second Carbon (C-2) of the guanine base, and the oxygen atom attached to the second Carbon (C-2) of the cytosine base.
Answer:
B. They can for covalent bonds with other atoms.
Explanation:
Carbon = King of the elements on the periodic table
For its proclivity to form stable covalent bonds with multivalent atoms.
The molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.
<u>Explanation:</u>
Molality is the measure of how much of amount of solute is dissolved in the solvent. So it is calculated as the ratio of moles of solute to the grams of solvent.

As in this case, the solute is NaCl and solvent is unknown. So the moles of solute is given as 1.34 moles and the mass of solvent is given as 2.47 kg.
Hence, 
Thus, the molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.
Hi, you've asked an incomplete question. However, I assumed you are referring to the article found on the Scientific American website.
Explanation:
<em>Remember,</em> according to that article we are told that scientists notice that these insects have a long nymphal (immature form before becoming adults) stage, one that can last up to 13 to 17 years on the ground before they leave the ground looking for mating partners.
Because it is only after mating occurs at this point that their eggs are laid, that is why scientists believe that cicadas only reproduce every 13 or 17 years.
Answer: A.mol/kg
The SI (international system) unit for molality is mol / kg, or solute moles per kg of peptides. A solution with a molality of 1 mol / kg is often described as "1 molal" or "1 m".