Question

• a hydrogen bond is a choose... between an atom of one molecule and a hydrogen atom of another molecule.
• dna contains choose... kind(s) of nucleotides.
• each dna nucleotide is made up of three parts: a nitrogenous base (or called a base) bonded to a choose... called deoxyribose, which is bonded to a(n) choose...

Explanation:

1. For the first blank: A hydrogen bond is an attractive force (specifically a dipole - dipole interaction, but in basic terms, an attraction) between an electronegative atom (like O, N, F) of one molecule and a hydrogen atom (that is covalently bonded to an electronegative atom) of another molecule. So the term is "weak attraction" (or more precisely, "attractive interaction", but in the context of basic biology/chemistry education, "weak attraction" or "bond" (though hydrogen bonds are not true chemical bonds but intermolecular forces) is used. However, the standard term here is "attraction" or "bond" (with the understanding of intermolecular force).
2. For the second blank: DNA is composed of 4 kinds of nucleotides: adenine, thymine, guanine, and cytosine. So the answer is "4".
3. For the third blank: Each DNA nucleotide has a nitrogenous base bonded to a sugar. The sugar in DNA is deoxyribose, which is a 5 - carbon sugar (a pentose). So the term here is "sugar" (specifically deoxyribose, but the blank is for the general category, so "sugar").
4. For the fourth blank: The third part of a DNA nucleotide (after the nitrogenous base and the sugar) is a phosphate group. So the answer is "phosphate group".

Answer:

• First blank: weak attraction (or attraction/bond, but "weak attraction" is more accurate for hydrogen bond's nature)
• Second blank: 4
• Third blank: sugar
• Fourth blank: phosphate group