Which of the following statements is true?
a.
most parts of the world do not have any natural resources.
b.
north america has many natural resources, but south america does not have any.
c.
most places on earth have the same amounts and types of natural resources.
d.
different places on earth have different kinds of natural resources

During crossing-over, a. genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles. b. nonsister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. c. one homologous chromosome of a tetrad is exchanged with another tetrad, resulting in new combinations of alleles. d. sister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. e. genetic material is exchanged between sister chromatids, resulting in new combinations of alleles.