Question

Organisms are classified as eukaryotes or prokaryotes based on their basic body structure. Which of the following is true of organisms and the type of genetic information they contain?

Question 9 options:

Both eukaryotes and prokaryotes contain DNA enclosed in membrane-bound nuclei


Both eukaryotes and prokaryotes contain DNA, but prokaryotes typically only have a single, circular chromosome

All eukaryotes and most prokaryotes contain DNA, but Archaebacteria only contain RNA


All eukaryotes contain DNA, and all prokaryotes contain only RNA

The flowering plant known as the snapdragon produces white, yellow, and crimson flowers. When a snapdragon that is homozygous for the gene for white flowers is crossed with a crimson snapdragon that is homozygous for the gene for crimson flowers, heterozygous offspring with pink flowers are produced. Which of the following terms correctly describes this phenomenon?
Question 17 options:

Mendelian inheritance


polygenic inheritance


pleiotropy


incomplete dominance

Punctuated equilibrium and gradualism are both models for evolutionary change, but they are very different theories. Which of the following statements is true of the evolutionary theory known as gradualism?
Question 19 options:

Several closely related species from isolated populations evolve rapidly


Fossils showing intermediate changes will not necessarily be found


Evolution occurs in spurts of rapid change


Speciation occurs gradually

Answer 1

Question 9: The right answer is B (the second one)

The two major types of cellular, prokaryotic and eukaryotic organisms.

* Prokaryotes are identified with bacteria: most live as single-cell organisms but some bacteria associate in a chain. Prokaryotes have their DNA in the cytoplasm of the cell.

* Eukaryotes have a nucleus, a compartment separated from the rest of the cellular contents, which contains the DNA.

Question 17: The right answer is incomplete dominance.

Incomplete-dominated genetic action is a type of genetic action where one of the alleles outweighs the other in the production of qualitative phenotypes, without the dominant allele completely overshadowing the heterozygous recessive allele. Two copies of the dominant allele are required to produce the dominant phenotype. Since the recessive allele can perform its function at the heterozygous stage, this genotype produces a phenotype (the heterozygous phenotype) which differs little from the dominant phenotype.

In our case the phenomenon of incomplete dominance gave a pink color (between white and crimson) instead of crimson color when the white flowering plant was mixed with the crimson flower plant.

Question 19: The right answer is Speciation occurs gradually.

Speciation is a term that means the formation of new species.

Gradualism is an evolutionary theory according to which new species occur by gradual transformation of ancestral species, by evolution.

These transformations are slow and regular. Otherwise expressed: evolutionary theory according to which speciation is gradually effected by small successive changes over long periods.