Regents Living Environment Test Preparation Practice

    Meiosis Fertilization Gametes And Zygote


    Base your answers to questions 12 on the passage below and on your knowledge of biology. Biologists have been studying the genes present in newborn twins.

    Twins Don’t Share Everything

    …Chemicals called epigenetic markers can be attached to those [inherited] genes, like flags or balloons hanging off the sides of the DNA ladder. These don’t just change the look of the genes. Like pieces of tape stuck over a light switch, these markers can force a gene to remain turned on or off. The type of marker scientists studied in the twins generally sticks the switch in the off position so that some proteins don’t get made. And that means the proteins’ jobs won’t get done.

    Every time a cell divides, new epigenetic markers may form. Foods, pollutants, and stress may all contribute to the development of new markers. So throughout our lives we tend to accumulate more and more. But a few are there from the day we’re born.

    …His [Jeffrey Craig’s] team found that newborn twins have markers attached to different genes from the very start. It’s true in identical twins, which come from the same fertilized egg. It’s also true in fraternal twins, which come from different fertilized eggs. However, fraternal twins had more such differences than identical twins did.

    Source: Science News for Students; July 31, 2012


    Base your answers to questions 17 on the information below and on your knowledge of biology.

    The testes of a human male produce gametes. The process that produces these gametes differs from the process that produces new skin cells in the same individual.


    Base your answers to questions 18 on the information and data table below and on your knowledge of biology.

    Peregrine falcons are an endangered species in New York State. This crow-sized predator feeds primarily on birds. Starting in the 1940s, exposure to the pesticide DDT in their prey caused declines in the peregrine falcon population. These pesticides caused eggshell thinning, which drastically lowered breeding success. By the early 1960s, peregrine falcons no longer nested in New York State. After the United States banned DDT in 1972, efforts were made to reintroduce peregrine falcons into the Northeast. Since the 1980s, the peregrine falcons are once again breeding in many areas of New York State.

    labs, lab, appendix A, laboratory check list, scientific inquiry, data organization, plot and interpretation fig: lenv-v202-exam_g15.png

    Directions: Using the information in the data table, construct a line graph on the grid provided, following the directions below.