1.The correct answer is D Since the time of Linnaeus, the classification of organisms into kingdom has significantly changed. Fungi have been classified as a separate kingdom (they have been classified under plants before) and the development of microscopy has enabled scientist to study microscopic organisms and classify them into the Protista and Monera kingdoms.
2.The correct answer is D The phylum is one of the highest ranks of classification, right under the rank of kingdom, so it contains a great number of species. For example, the phylum of Arthropoda contains all the insect, spider, crustacean and millipede species.
3.The correct answer is B Before the methods of genetics and molecular biology research were developed, species were classified only based on their physical appearance. But now, we can determine how closely related species are by their genes as well. This solves the problem of species that have developed convergent traits as a response to similar environments, but that, in fact, are not genetically similar.
4.The correct answer is C The classification of viruses has always been a difficult question for scientists. Viruses have their own genetic material enclosed in a protein coat, but they can not reproduce on their own since they need the metabolism and the genetic machinery of other cells to survive.
5.The correct answer is D The two species are definitely members of the Eukarya domain because they have nuclei. All of the other domains, Bacteria, and Archaea lack all organelles including the nuclei. If both of the species produce eggs, they may be members of the animal kingdom. 6. The correct answer is A Even though both bacteria and archaea are single-celled prokaryotes the differences between them are great. Their cell walls and cell membranes are built from different lipids and the enzymes that have a role in the central dogma differ significantly.
7.the correct answer is B Sexual reproduction in eukaryotes has a purpose of exchanging the genetic material between two individuals. The process of conjugation in bacteria is very similar to sexual reproduction, but there are no specialized sex cells and the cells do not form haploid cells through meiosis.
8. The correct answer is D Natural selection has filtered the population of bacteria. Only the individuals resistant to the antibiotic have managed to survive and leave offspring, producing a population of bacteria that is solely consisted of antibiotic-resistant individuals.
9. The correct answer is D Red algae are autotrophic organisms. This means that they are producers of food, in this case, they can produce sugars trough conversion of sunlight in the chloroplasts. The amoeba must consume other organisms or organic particles to survive, and the only way for it to do it is through the process of endocytosis since they lack mouths.
10. The correct answer is B Molds are fungi that are dependant on moisture. They are not photosynthetic and they lack flagella, so the most efficient way to eradicate molds would be to dry out the area and the lack of moisture will cause the disappearance of the mold.
Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere.
