Hydrogen bonds
Guanine-cytosine and adenine-thymine <em>hydrogen bonds</em> hold the strands of a DNA helix together.
Answer:
(B) HNO3 + NaOH
Explanation:
Hello,
In this case, for the production of sodium nitrate a substance having the sodium as a cation should react with another substance having the nitrate anion. Moreover, neutralization reactions are carried out when bases react with acids, such is the case of nitric acid and sodium hydroxide:

Thus, the answer is (B) HNO3 + NaOH as the other options involve salts rather than acids or bases as starting reactants.
Regards.
Answer:
please put the full question
Explanation:
The statement that accurately describes dark matter is that It is invisible and It does not emit electromagnetic radiation.
<h3>What is dark matter?</h3>
Dark matter is defined as the particles that makes up most of the mass of galaxies and galaxy clusters. They are also responsible for the way galaxies are organized on grand scales.
The features or characteristics of dark matter is that they are invisible and they do not emit electromagnetic radiation.
Learn more about electromagnetic radiation here:
brainly.com/question/1408043
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Answer:
n = 2.1 mol
Explanation:
Given data:
Number of moles of gas = ?
Volume of gas = 56.3 L
Pressure of gas = 0.899 atm
Temperature of gas = 20°C (20+273 = 293 k)
Solution:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
0.899 atm × 56.3 L = n × 0.0821 atm.L/ mol.K × 293 k
50.614 atm.L = n × 24.055 atm.L/ mol
n = 50.614 atm.L / 24.055 atm.L/ mol
n = 2.1 mol