When deciding on new environmental policies and laws, which term is used to describe the comparison between benefits and costs of human activities?

The northern snakehead is a type of Asian fish that eats smaller fish and is adapted to a freshwater habitat. The presence of these fish in American waters is of concern because it might offer too much competition to native

In a food web, which type of organism receives energy from the other three types?

An ameba is a single-celled, heterotrophic organism. In order to meet its energy needs, it relies directly on the interaction of which cell structures?

Recently, oil from a wrecked tanker resulted in a disaster in ecosystems containing many unique species. The potential loss of these species could result in

Which process occurs at each link in a food chain?

Genetic recombination, production of more offspring than can survive, and struggling with the challenges of the environment are all concepts associated with

Mistletoe is a plant that lives on the branches of trees. The mistletoe plant sends its roots in through the bark of trees and takes away water and minerals that the tree needs. In this situation, the mistletoe plant is

An example of a population in which evolution could take place in a relatively short period of time could be

Butterflies exposed to radiation leaking from a damaged nuclear power plant in Japan have been observed to have malformed legs, antennae, and wings. For future butterfly generations to have these similar structural abnormalities, gene mutations must be present in the affected butterflies’

The diagram below illustrates the release of chemical A from a human cell in response to a specific stimulus. Which cell structure plays a direct role in the release of this chemical from the cell?

A rich variety of genetic material in an ecosystem will

The process of sexual reproduction is an important part of the process of evolution. One reason for this is that meiosis and fertilization directly produce many new

A garlic bulb consisting of several smaller sections called cloves is shown below. If cloves are separated from the bulb and later planted in a garden, a new garlic bulb will grow from each. In this way, a home gardener could grow a whole crop of genetically identical garlic plants starting with one bulb. As a result of this procedure, the gardener would

When humans place grass clippings and other yard waste in landfills, they are most directly interfering with the natural process of

Which statement is an example of a feedback mechanism in humans?

Many disorders are due to the inability of an individual to break down a particular chemical. Sometimes these disorders can be treated by giving the affected individual the appropriate

The removal of the predator populations from an ecosystem would most likely result in

Two new wind turbines have recently been built within the Eiffel Tower in Paris. The power that these turbines generate will be enough to power the entire first floor of the tower, including the restaurants, shops, and exhibits. A benefit of using wind power as an alternative source of energy is that it

In the photograph below, two fish are displaying a behavior commonly observed among pairs of rabbitfish. While one has its head down feeding on coral, the other remains upright, alert for predators. This behavior continues to be present in the rabbitfish population because

The fast food industry in the United States buys many russet potatoes from farmers. Therefore, most potato farmers grow russet potatoes. If farmers continue to plant the same crop in the same fields year after year without putting additives into the soil, the end result could be

A corn field includes corn plants, mice, hawks, and various insects, fungi, and bacteria. Which nutritional role is correctly paired with organisms that carry out that role?

Each female housefly can lay approximately 500 eggs in a lifetime. She does this in several batches of about 75 to 150 eggs. Within a day, larvae (maggots) hatch from the eggs. They live and feed on organic material, such as garbage and feces. Scientists have calculated that a pair of flies beginning reproduction in April could be the ancestors of 191,010,000,000,000,000,000 flies by August. Which statement best explains why this does not happen?

Which sequence best represents the levels of organization in a paramecium, a single-celled organism?

More than 100 years ago, Earth’s atmosphere contained about 280 parts per million (ppm) of carbon dioxide. It is predicted that by the year 2050, the level of carbon dioxide in the atmosphere could reach 700 ppm, greatly increasing Earth’s temperature. It has been suggested that growing more green plants would help to slow this increase. The best explanation for why increased numbers of plants would help is that plants

The brown tree snake was accidentally introduced to the island of Guam during World War II. Since then, this snake has caused the extinction of twelve native bird species by eating their eggs and young. One negative result of this snake’s introduction was most likely

The Extinction of the Passenger Pigeon

In the early 1800s, the passenger pigeon was the most abundant bird species in North America. These pigeons traveled in flocks sometimes larger than a billion birds. The enormous flock sizes helped protect them from predation by foxes, lynx, owls, and falcons. It also helped them outcompete other animals (squirrels, chipmunks) for chestnuts and acorns, their main food source. Unfortunately, this flocking behavior made the passenger pigeons easy targets for the people who killed them for food. The invention of the telegraph to broadcast flock locations to hunters and the expansion of the railroads to ship the pigeons to new food markets had devastating results. By the 1890s, their numbers had dwindled dramatically, with flocks only numbering in the hundreds. In 1914, the passenger pigeon became extinct when the last member of the species died at the Cincinnati Zoo. Which factor contributed least to the extinction of the passenger pigeon species?

The Extinction of the Passenger Pigeon

In the early 1800s, the passenger pigeon was the most abundant bird species in North America. These pigeons traveled in flocks sometimes larger than a billion birds. The enormous flock sizes helped protect them from predation by foxes, lynx, owls, and falcons. It also helped them outcompete other animals (squirrels, chipmunks) for chestnuts and acorns, their main food source. Unfortunately, this flocking behavior made the passenger pigeons easy targets for the people who killed them for food. The invention of the telegraph to broadcast flock locations to hunters and the expansion of the railroads to ship the pigeons to new food markets had devastating results. By the 1890s, their numbers had dwindled dramatically, with flocks only numbering in the hundreds. In 1914, the passenger pigeon became extinct when the last member of the species died at the Cincinnati Zoo. A direct result of the rapid decline of the passenger pigeon population was most likely

The Extinction of the Passenger Pigeon

In the early 1800s, the passenger pigeon was the most abundant bird species in North America. These pigeons traveled in flocks sometimes larger than a billion birds. The enormous flock sizes helped protect them from predation by foxes, lynx, owls, and falcons. It also helped them outcompete other animals (squirrels, chipmunks) for chestnuts and acorns, their main food source. Unfortunately, this flocking behavior made the passenger pigeons easy targets for the people who killed them for food. The invention of the telegraph to broadcast flock locations to hunters and the expansion of the railroads to ship the pigeons to new food markets had devastating results. By the 1890s, their numbers had dwindled dramatically, with flocks only numbering in the hundreds. In 1914, the passenger pigeon became extinct when the last member of the species died at the Cincinnati Zoo. The extinction of the passenger pigeon illustrates that

To study how bacteria respond to antibiotics, four paper discs, three treated with different antibiotics and one treated with water, were placed on a nutrient source with bacteria and left for 24 hours. The water and the antibiotics on the discs diffused into the nutrient source. If the antibiotic stopped the bacteria from growing, a circular area of no bacterial growth around the discs could be seen. After 24 hours, the results represented by the diagram demonstrate

To study how bacteria respond to antibiotics, four paper discs, three treated with different antibiotics and one treated with water, were placed on a nutrient source with bacteria and left for 24 hours. The water and the antibiotics on the discs diffused into the nutrient source. If the antibiotic stopped the bacteria from growing, a circular area of no bacterial growth around the discs could be seen. In this experiment, the purpose of using a disc treated with water is that it

The diagram below represents some stages in the process of development. Stage 2 represents a cell that

The table below shows the results of a study on the lifespan of 115 individual song sparrows. The two most likely factors contributing to the decline in the number of these 115 sparrows during year 1 were

The diagnostic test for HIV, the virus that causes AIDS, involves testing the blood for antibodies associated with this pathogen. Antibodies are produced when the body

Body cells include nerve cells and muscle cells. Each makes a number of different proteins. For example, nerve cells make cholinesterase and muscle cells make myosin. Which statement best compares the DNA normally found in these two types of cells in an individual?

The chart below compares the greenhouse gas emissions of several fuel sources. An accurate prediction that could be made regarding the information shown in the chart is that

Studies have shown that children are especially vulnerable to the effects of ultraviolet (UV) radiation. Tanning beds expose the skin to nearly ten times as much UV radiation as natural sunlight. With that knowledge, a law was passed in New York State to prevent individuals under the age of 18 from using tanning beds. Which statement best explains why UV radiation is so harmful?

The diagram shows a small segment of DNA taken from a gene before and after it is copied. Changes made during the copying process are represented by * in the diagram. The errors indicated by * could affect a cell by

The diagram shows a small segment of DNA taken from a gene before and after it is copied. Changes made during the copying process are represented by * in the diagram. The process by which a cell copies its DNA before it divides is

Invasive species have damaged agricultural crops all over the world. One study, completed in Japan, calculated the number of invasive insect species present in Japan from 1880 to 1990. Some of the data are recorded in the table below. In the last decade of this study, there was a decrease in the number of invasive insects that entered Japan. One likely reason for this decrease is that people have

An investigation was conducted to compare two different types of plants. A student used a microscope to observe the cells in a cross section of a lilac leaf (diagram A) and a cell from the leaf of a freshwater plant (diagram B). Which row in the chart below correctly identifies the structure labeled Y in both diagrams and the process it performs?

An investigation was conducted to compare two different types of plants. A student used a microscope to observe the cells in a cross section of a lilac leaf (diagram A) and a cell from the leaf of a freshwater plant (diagram B). Which technique could be used to make the structures in the cells more visible when using a compound light microscope?

A procedure used in paper chromatography is represented below:

The student is preparing two strips of paper for a chromatography activity. After adding a dot of the ink from the marker pen to the line on the paper on the right, the next step should be to place the strips in a beaker of solvent with the solvent level

Based on these results, it can be concluded that the specific protein that was added to the samples was

The diagram represents red blood cells placed in three test tubes, each containing a different salt solution. Which statement best describes solution C?

The diagram represents red blood cells placed in three test tubes, each containing a different salt solution. Which solution would be most similar in concentration to the normal internal environment of the human circulatory system?

A student is viewing a plant stem cross section using a compound light microscope. What parts of the microscope should the student use to bring the image into focus?

A rare tropical plant was found to have medicinal properties. A search was conducted to find other plants that are closely related to the rare plant. Which combination of characteristics would best identify the plant most closely related to the original one?