Structures represented in the illustration below are found in the lower epidermis of a plant leaf. The illustration at right shows the response to a certain environmental condition. The response represented in the illustration would most likely be caused by

How is information for a specific protein carried on the DNA molecule?

The food web shows the flow of energy through a sagebrush-steppe ecosystem. Which of these organisms are in a trophic level that receives a larger percentage of the energy captured by the producers than the percentage received at the bats’ trophic level?

Fireflies emit light. The production of light by an organism is called bioluminescence. To generate visible light, cells in a firefly’s tail produce thousands of luciferase enzymes. Luciferase binds to a chemical called luceferin. Once bound, the luciferase enzyme speeds up a chemical reaction that combines an oxygen molecule and luciferin to produce oxyluceferin. This reaction requires energy and releases light. Which of the following best describes how the luciferase enzyme speeds up the chemical reaction?

An analysis of DNA and RNA sequences can be used to classify organisms. A dendrogram, such as the one shown, is based on molecular data. It can be used to represent evolutionary relationships within a group of organisms that are hypothesized to have descended from a common ancestor. Which statement is best supported by the information in this dendrogram?

Facial dimples and free earlobes are both considered dominant human traits. What are the expected phenotypes of the offspring of a female with dimples and free earlobes (DDFf) and a male with no dimples and attached earlobes (ddff)?

Adult mountain lions (Puma concolor) are almost 2 meters long. They have a black spot over each eye. The common names used throughout the United States for this species are listed. Why is it best for scientists to use the name from the standardized taxonomic system?

The internal transport of water and minerals in plants requires that two systems work together. Which diagram correctly describes how the two systems accomplish this?

At birth, Himalayan rabbits are usually white over their entire bodies. But when parts of their bodies reach temperatures below 35°C, a pigment that causes these parts to turn black is produced. Which of the following is most likely the cause of this phenomenon?

All the animals to the right of the hagfish would have the common characteristic of

The differences between two molecules include the type of sugar that forms a section of the molecules and the identity of one of the four nitrogenous bases that make up another section of the molecules. These two molecules are

Plants have developed many methods of seed dispersal. The table below shows seeds to two different species. How has the seed dispersal method developed by these plants given them a reproductive advantage?

The table lists the types of white blood cells found in humans, indicates how abundant they are, and describes their functions. The two most abundant types of white blood cells may both be involved in a response to which of these?

A science class is planning a field trip to a local farm that has a large pond. Which of the following lists the order of biological organization from smallest to largest that the students can expect to find at the pond?

Some students used vinegar to dissolve a way the shells of three eggs and used these eggs as models of human red blood cells. The students observed the changes in the eggs when they were placed in different solutions. Which statement best describes the role of the cell membrane in this model?

Animal body systems often coordinate their actions to carry out specific functions for the whole animal. Which of these correctly describes the interaction of two biological systems for a specific purpose in the human body?

A student is asked to draw a food web in which the same organism is a primary consumer as well as a secondary consumer. How should the organism be represented in the food web?

Which of these models of a DNA strand (below) shows bases that are complementary to the ones on the student’s DNA model (above)?

Three species of lizards of the genus Gallotia are found on the Canary Islands, a chain of seven volcanic islands off the west coast of Africa. The easternmost island, Lanzarote, is the oldest, while the westernmost island, El Hierro, is the youngest. The distribution of lizard species is shown on the map below. Which statement about the ancestry of the lizards from the genus Gallotia is best supported by this information?