Question: Q: Q: What type of pollutants enter the air directly?   Read this paragraph and choose the correct option from the provided answers:  Primary pollutants enter the air directly. Some are released by natural processes, like ash from volcanoes. Most are released by human activities. Carbon oxides are released when fossil fuels burn.   Choices:  - secondary  - liquid  - carbon  - primary   A:
A: primary


Q: Q: Adult tunicates also develop a sac, called a what?   Read this paragraph and choose the correct option from the provided answers:  24.2 Subphylum Urochordata The tunicates are located in this subphylum. Along with the subphylum Cephalochordata, these two subphyla make up the invertebrate chordates. Only the tunicate larvae have notochords, nerve cords, and postanal tails. Most adult tunicates are sessile, filter-feeders which retain their pharyngeal slits. Adult tunicates also develop a sac, called a tunic, which gives tunicates their name. Cilia beating within the turnicate cause water to enter the incurrent siphon. The water enters the body, passes through the pharyngeal slits, and leaves the body through the excurrent siphon. Undigested food is removed through the anus. Tunicates are hemaphrodites and can reproduce asexually through budding. In urochordates notochord is confined to larval tail. These lack cranium. These have an open type of circulatory system. Excretion is by neural gland,nephrocytes.   Choices:  - hood  - skirt  - frill  - tunic   A:
A: tunic


Q: Q: What is used to prevent some infectious diseases?   Read this paragraph and choose the correct option from the provided answers:  Vaccines are available for some infectious diseases. For example, there are vaccines to prevent measles, mumps, whooping cough, and chicken pox. These vaccines are recommended for infants and young children.   Choices:  - radiation  - pathogens  - pesticides  - vaccines   A:
A: vaccines


Q: Q: What is the rate at which a specific allele appears within a population called?   Read this paragraph and choose the correct option from the provided answers:  The allele frequency (or gene frequency) is the rate at which a specific allele appears within a population. Until now we have discussed evolution as a change in the characteristics of a population of organisms, but behind that phenotypic change is genetic change. In population genetics, the term evolution is defined as a change in the frequency of an allele in a population. Using the ABO blood type system as an example, the frequency of one of the alleles, IA, is the number of [1] copies of that allele divided by all the copies of the ABO gene in the population. For example, a study in Jordan found a frequency of IA to be 26.1 percent. The IB and I0 alleles made up 13.4 percent and 60.5 percent of the alleles respectively, and all of the frequencies added up to 100 percent. A change in this frequency over time would constitute evolution in the population. The allele frequency within a given population can change depending on environmental factors; therefore, certain alleles become more widespread than others during the process of natural selection. Natural selection can alter the population’s genetic makeup; for example, if a given allele confers a phenotype that allows an individual to better survive or have more offspring. Because many of those offspring will also carry the beneficial allele, and often the corresponding phenotype, they will have more offspring of their own that also carry the allele, thus, perpetuating the cycle. Over time, the allele will spread throughout the population. Some alleles will quickly become fixed in this way, meaning that every individual of the population will carry the allele, while detrimental mutations may be swiftly eliminated if derived from a dominant allele from the gene pool. The gene pool is the sum of all the alleles in a population. Sometimes, allele frequencies within a population change randomly with no advantage to the population over existing allele frequencies. This phenomenon is called genetic drift. Natural selection and genetic drift usually occur...   Choices:  - allele commonness  - trait frequency  - allele rarity  - allele frequecy   A:

Answer: A: allele frequecy