If crossing over and independent assortment ceased to occur,
a. genetic variation would decline rapidly, with sperm or ova having the same alleles.
b. sperm will always have the same alleles, but ova will always have different alleles.
c. ova will always have the same alleles, but sperm will always have different alleles.
d. sperm or ova would alternate between the types of alleles they will contain.

Genetic variation would decline rapidly, with sperm or ova having the same alleles.

Explanation:

Crossing over is the exchange of genetic material between the chromatids of homologous chromosomes. It results in the formation of recombinant chromatids that have new combinations of maternal and paternal alleles. The gametes with recombinant alleles impart genetic variations to the progeny.

Likewise, an independent assortment of homologous chromosomes to the opposite poles during anaphase I of meiosis I result in the packing of alleles of a gene independent of that of the other gene. Independent assortment produces some gametes with new gene combinations and the other with parental gene combinations.

If crossing over and independent assortment cease to occur, male and female gametes will have the same alleles due to the absence of any source of recombination and the genetic variation in the progeny would be reduced.  

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.