Living Environment January 2003 Questions Answer Keys
The University of the State of New York
Regents High School Examination
Living Environment
Thursday, January 30, 2003 — 9:15 a.m. to 12:15 p.m., only
Student Name _____________________________________________________________
School Name ______________________________________________________________
Directions (1–30): For each statement or question, write on the separate answer sheet the number of the word or expression that, of those given, best completes the statement or answers the question.
1. A biologist reported success in breeding a tiger with a lion, producing healthy offspring. Other biologists will accept this report as fact only if
- (1) research shows that other animals can be crossbred
- (2) the offspring are given a scientific name
- (3) the biologist included a control in the experiment
- (4) other researchers can replicate the experiment
2. The diagram below represents a pyramid of energy in an ecosystem.

Which level in the pyramid would most likely contain members of the plant kingdom?
- (1) A
- (2) B
- (3) C
- (4) D
3. Which condition would cause an ecosystem to become unstable?
- (1) only heterotrophic organisms remain after a change in the environment
- (2) a slight increase in the number of heterotrophic and autotrophic organisms occurs
- (3) a variety of nonliving factors are used by the living factors
- (4) biotic and abiotic resources interact
4. Nerve cells are essential to an animal because they directly provide
- (1) communication between cells
- (2) transport of nutrients to various organs
- (3) regulation of reproductive rates within other cells
- (4) an exchange of gases within the body
5. Certain bacteria produce a chemical that makes them resistant to penicillin. Since these bacteria reproduce asexually, they usually produce offspring that
- (1) can be destroyed by penicillin
- (2) mutate into another species
- (3) are genetically different from their parents
- (4) survive exposure to penicillin
6. A sudden change in the DNA of a chromosome can usually be passed on to future generations if the change occurs in a
- (1) skin cell
- (2) liver cell
- (3) sex cell
- (4) brain cell
7. A change in the order of DNA bases that code for a respiratory protein will most likely cause
- (1) the production of a starch that has a similar function
- (2) the digestion of the altered gene by enzymes
- (3) a change in the sequence of amino acids determined by the gene
- (4) the release of antibodies by certain cells to correct the error
8. Many vaccinations stimulate the immune system by exposing it to
- (1) antibodies
- (2) enzymes
- (3) mutated genes
- (4) weakened microbes
9. The data in the graph below show evidence of disease in the human body.

A disruption in dynamic equilibrium is indicated by the temperature change between points
- (1) A and B
- (2) B and C
- (3) C and D
- (4) E and F
10. The diagram below represents events involved as energy is ultimately released from food.

Which row in the table below best represents the chain of Xs and letters A and B in the diagram?

11. In the diagram below, the dark dots indicate small molecules. These molecules are moving out of the cells, as indicated by the arrows. The number of dots inside and outside of the two cells represents the relative concentrations of the molecules inside and outside of the cells.

ATP is being used to move the molecules out of the cell by
- (1) cell A, only
- (2) cell B, only
- (3) both cell A and cell B
- (4) neither cell A nor cell B
12. The diagrams below represent some steps in a procedure used in biotechnology

Letters X and Y represent the
- (1) hormones that stimulate the replication of bacterial DNA
- (2) biochemical catalysts involved in the insertion of genes into other organisms
- (3) hormones that trigger rapid mutation of genetic information
- (4) gases needed to produce the energy required for gene manipulation
13. According to some scientists, patterns of evolution can be illustrated by the diagrams below.

Which statement best explains the patterns seen in these diagrams?
- (1) The organisms at the end of each branch can be found in the environment today.
- (2) The organisms that are living today have all evolved at the same rate and have undergone the same kinds of changes.
- (3) Evolution involves changes that give rise to a variety of organisms, some of which continue to change through time while others die out.
- (4) These patterns cannot be used to illustrate the evolution of extinct organisms.
14. Which statement best illustrates a rapid biological adaptation that has actually occurred?
- (1) Pesticide-resistant insects have developed in certain environments.
- (2) Scientific evidence indicates that dinosaurs once lived on land.
- (3) Paving large areas of land has decreased habitats for certain organisms.
- (4) The characteristics of sharks have remained unchanged over a long period of time.
15. During meiosis, crossing-over (gene exchange between chromosomes) may occur. Crossingover usually results in
- (1) overproduction of gametes
- (2) fertilization and development
- (3) the formation of identical offspring
- (4) variation within the species
16. The diagram below illustrates the change that occurred in the physical appearance of a rabbit population over a 10-year period.

Which condition would explain this change over time?
- (1) a decrease in the mutation rate of the rabbits with black fur
- (2) a decrease in the advantage of having white fur
- (3) an increase in the advantage of having white fur
- (4) an increase in the chromosome number of the rabbits with black fur
17. The diagram below represents some stages of early embryonic development.

Which process is represented by the arrows in the diagram?
- (1) meiosis
- (2) fertilization
- (3) mitosis
- (4) evolution
18. The reproductive system of the human male produces gametes and
- (1) transfers gametes to the female for internal fertilization
- (2) produces enzymes that prevent fertilization
- (3) releases hormones involved in external fertilization
- (4) provides an area for fertilization
19. Blood can be tested to determine the presence of the virus associated with the development of AIDS. This blood test is used directly for
- (1) cure
- (2) treatment
- (3) diagnosis
- (4) prevention
20. The equation below represents a summary of a biological process.
carbon dioxide + water → glucose + water + oxygen
This process is completed in
- (1) mitochondria
- (2) ribosomes
- (3) cell membranes
- (4) chloroplasts
21. In a stable, long-existing community, the establishment of a single species per niche is most directly the result of
- (1) parasitism
- (2) interbreeding
- (3) competition
- (4) overproduction
22. The diagram below represents a developing bird egg.

What is the primary function of this egg?
- (1) food supply for predators to preserve predator populations
- (2) adaptation to allow maximum freedom for parent birds
- (3) continuation of the species through reproduction
- (4) preservation of the exact genetic code of the parent birds
23. The diagram below represents part of the human female reproductive system.

Fertilization and development normally occur in structures
- (1) 1 and 5
- (2) 2 and 4
- (3) 3 and 1
- (4) 4 and 5
24. The flow of energy through an ecosystem involves many energy transfers. The diagram below summarizes the transfer of energy that eventually powers muscle activity.
Sun → Food → ATP → Muscle Activity
The process of cellular respiration is represented by
- (1) arrow A, only
- (2) arrow B, only
- (3) arrow C, only
- (4) arrows A, B, and C
25. The presence of parasites in an animal will usually result in
- (1) an increase in meiotic activity within structures of the host
- (2) the inability of the host to maintain homeostasis
- (3) the death of the host organism within twentyfour hours
- (4) an increase in genetic mutation rate in the host organism
26. In Texas, researchers gave a cholesterol-reducing drug to 2,335 people and an inactive substitute (placebo) to 2,081. Most of the volunteers were men who had normal cholesterol levels and no history of heart disease. After 5 years, 97 people getting the placebo had suffered heart attacks compared to only 57 people who had received the actual drug. The researchers are recommending that to help prevent heart attacks, all people (even those without high cholesterol) take these cholesterol-reducing drugs. In addition to the information above, what is another piece of information that the researchers must have before support for the recommendation can be justified?
- (1) Were the eating habits of the two groups similar?
- (2) How does a heart attack affect cholesterol levels?
- (3) Did the heart attacks result in deaths?
- (4) What chemical is in the placebo?
27. What is represented by the sequence below?

- (1) a feedback mechanism in multicellular organisms
- (2) an immune response by cells of the pancreas
- (3) differentiation of organic molecules
- (4) the disruption of cellular communication
28. In an ecosystem, which component is not recycled?
- (1) water
- (2) energy
- (3) oxygen
- (4) carbon
29. Vultures, which are classified as scavengers, are an important part of an ecosystem because they
- (1) hunt herbivores, limiting their populations in an ecosystem
- (2) feed on dead animals, which aids in the recycling of environmental materials
- (3) cause the decay of dead organisms, which releases usable energy to herbivores and carnivores
- (4) are the first level in food webs and make energy available to all the other organisms in the web
30. “Natural ecosystems provide an array of basic processes that affect humans.”
Which statement does not support this quotation?
- (1) Bacteria of decay help recycle materials.
- (2) Trees add to the amount of atmospheric oxygen.
- (3) Treated sewage is less damaging to the environment than untreated sewage.
- (4) Lichens and mosses living on rocks help to break the rocks down, forming soil.
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