The green frog (Lithobates clamitans clamitans) is found in many parts of the United States. The table contains some information about this frog. Why does the ability to lay 1,000 to 5,000 eggs increase the fitness of the species

L. clamitans clamitans?

During meiosis, homologous chromosomes exchange genetic material. This exchange of

genetic material —

As a fertilized egg divides, the cells differentiate because they —

The photograph shows monarch butterflies landing on plants where there are thousands of other monarch butterflies. These butterflies feed on milkweed plants as they travel south for the winter, covering distances of 5,000 km or more each year. However, the population of these butterflies has been steadily declining over the last 20 years. What is the most likely reason the population of these butterflies has been declining?

Bactrian camels, dromedaries, llamas, and alpacas are all members of the same taxonomic family, Camelidae. Members of this family all have two toes, no hooves, true canine teeth, and a split upper lip. The family Camelidae originated in North America. The physical features

of animals in this family and the family’s geographical origin provide evidence that all these

animals —

Which statement best describes the relationship between the products of photosynthesis and the reactants in cellular respiration?

Health professionals sometimes recommend nutritional supplements that contain a variety of species of bacteria to promote good digestive health. The product label for one of these supplements is shown. Why does this type of bacteria-filled supplement benefit human health instead of causing illness?

The initial steps in gene expression are modeled below. Double-stranded DNA first unwinds into two strands. Which process and product are represented in Diagram 2?

The diagram shows cells in different phases of mitosis. A student is trying to find a cell in a particular phase of mitosis. The student is looking for evidence that spindle fibers are separating the chromosomes to ensure that each new nucleus has one copy of each chromosome. Which cell is in the phase of mitosis that the student is searching for?

The quiver tree grows in desert areas in southern Africa. In recent decades average temperatures have been rising in southern Africa. Scientists predict that this warming trend will continue. Quiver trees in the hottest parts of their range near the equator are dying, but quiver trees at high elevations or in parts of the range that are farther from the equator are growing and reproducing. Which of these best explains what is happening to the quiver tree population in southern Africa?

Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases?

This diagram shows cellular activity across a cell membrane. Which two processes does this diagram most directly model?

In the early 1980s scientists were able to produce two biomolecules by splicing a human gene into the bacterium E. coli to make recombinant human insulin and growth hormone. Which statement best explains why this experiment was successful?

Cells pass through a G₂ checkpoint before entering mitosis. Ideally, if DNA damage is 2 detected, the cells do not enter mitosis until the damage is repaired. Why is DNA damage repaired before cells enter mitosis?

The table shows a DNA sequence and three types of mutations that can change the DNA sequence. Which mutation will cause translation to stop?

People who have Alzheimer’s disease experience an increasing loss of brain function and cognition over time. Alzheimer’s is characterized by a buildup of abnormal protein fragments that damage brain cells. Recently scientists have discovered an enzyme, BACE2, that decreases these abnormal protein fragments in the brain of a person with Alzheimer’s disease. Which statement explains how BACE2 most likely works?

The complex carbohydrates pictured below are made by linking molecules of glucose.

In 2010, scientists excavated a skull fossil that provides evidence of a newly discovered species of big cat. Based on the evidence, scientists hypothesize that big cats branched off from smaller wild cats about 6 million years ago. Which of these resources did the scientists most likely rely on to form their hypothesis?

Chickens can have different types of feathers. Frizzled feathers curl toward a chicken’s head. Assume that feather type is determined by a single gene and that the allele for frizzled feathers is dominant over the allele for straight feathers. In a cross between two chickens with straight feathers, what percentage of the offspring can be expected to have frizzled feathers? Draw a Punnet Square!!!!

Oncogenes are mutated forms of genes. Oncogenes can transform a cell into a tumor cell. Some tumor cells are benign, while others are malignant. How does the presence of an oncogene lead to the formation of a tumor?

Each strand of a DNA molecule contains nitrogenous bases that pair with other nitrogenous bases in very specific ways. A diagram of a section of DNA is shown. Which DNA strand is complementary to the one shown above?

A prey population consists of individuals with a variety of running speeds. The adaptation that allows some of these animals to run fast would be an example of natural selection if it helps them —

The 1918 influenza epidemic killed between 50 million and 100 million people worldwide. This epidemic happened near the end of World War I. More people died from the influenza epidemic than were killed in the war. Which of the following explains why this virus was so deadly worldwide?

The amount of energy the producers in this energy pyramid provide the primary consumers is 54,000 joules. From this amount, 540 joules are provided to the tertiary consumers. Based on this model, how much of the energy was provided to secondary consumers?

Food webs such as the one shown were first used in 1927 by the animal ecologist Charles Elton. The food web below represents the feeding relationships among organisms in an Alaskan ecosystem. An environmental change that removed which of these organisms from the ecosystem would cause the most instability in the ecosystem?

During the final stages of human gestation, receptors for the hormone oxytocin increase on the smooth muscle cells of the uterus. The release of oxytocin during labor stimulates the smooth muscle tissue in the wall of the uterus. The vigorous contraction of the uterine smooth muscle helps push the baby through the birth canal so that delivery can occur. This process involves the interaction of which organ systems?

The photograph shows monarch butterflies landing on plants where there are thousands of other monarch butterflies. These butterflies feed on milkweed plants as they travel south for the winter, covering distances of 5,000 km or more each year. However, the population of these butterflies has been steadily declining over the last 20 years. What is the most likely reason the population of these butterflies has been declining?

While visiting a national park, a student encounters an unfamiliar organism in a damp area near a body of water. The student notes that the organism is about 10 cm long, has four legs, and has a tail. The organism is black with small white spots on its smooth, moist skin. It also appears to have an internal skeletal system. To which class does the organism most likely belong?

During ecological succession, how does the growth of young hardwoods affect the organisms living in an ecosystem?

Some relationships between different organisms are shown in the table. Which table correctly identifies each type of interaction described?

Cytokinins are a class of plant hormones that help regulate growth by promoting cell division. Cytokinins are produced mainly in meristematic tissue, where most plant growth occurs. Which system carries cytokinins produced in the roots to the rest of the plant?

Scientists studying illnesses caused by chemically contaminated food conduct research to minimize the effects of these diseases on society. These chemicals harm the body through interactions between the digestive system and the immune system. Scientists conducting this research are likely to describe which of these interactions between the digestive and immune systems?

Kidneys are part of the excretory system in a human body. They purify the impure blood and send it back to the rest of the body. Which system is mainly responsible for the transport of plasma to the kidneys?

Part of a hydrothermal vent food web is represented in the diagram. Which organisms are both secondary and tertiary consumers in this food web?

Five general characteristics of organisms in kingdoms Plantae or Fungi are listed in the box. Which table correctly lists the characteristics of the organisms in the two kingdoms?

Several structures work together to allow flowering plants to reproduce. The diagram shows a typical flower. Which table correctly identifies the function of each structure or group of structures in the reproduction of the plant?

The picture shows a 3-D model of a virus called a bacteriophage. Bacteriophages can infect bacteria such as E. coli. In what way are the bacteriophage and E. coli alike?

This dichotomous key can be used to identify some conifers. Based on the key, which of these best describes the leaves and cones of the long-leaf pine?

Which of the following is most likely to cause the greatest disruption to an ecosystem?

The table lists and describes three types of cells from prepared slides that students observed with a microscope. Which of these sets of slides could students have used for their observations? Hint: Red blood cells are also known as erythrocytes.

Which statement best describes the differences in species diversity between an ecosystem beginning the process of primary succession and one beginning the process of secondary succession?

The photograph shows a laboratory investigator examining samples of DNA in a procedure called PCR, or polymerase chain reaction. Using PCR, the investigator can create thousands or even millions of copies of a fragment of DNA for closer investigation. In which of these situations would PCR be most useful?

The graph models core body temperature during a rapid change in environmental conditions. Which statement explains the pattern in the graph?

The table shows some observations made by four students during a field trip to a nature area. Which student made observations of a community of organisms?

Atmospheric nitrogen has to be combined with other elements, or fixed, in order to be used by plants. Lightning is one way that nitrogen is fixed. When lightning occurs, the extreme heat breaks the bonds in nitrogen molecules, allowing nitrogen to combine with oxygen and form nitrogen oxides. In what way is most of the nitrogen fixed by lightning made available for use by plants?

Plants called sundews have rounded green leaves with many hair-like structures. The ends of these structures contain enzymes in a sticky liquid that looks like nectar or moisture, as shown in the picture. The hairs do not react to dust or nonliving material but will bend inward when insects get caught in the sticky liquid. Sundews digest trapped insects over a period of a few days. Based on this information, what functions do the specialized leaves of sundews perform?

Scientists around the world use a standardized taxonomic system. Why would scientists want to use a taxonomic system that is standardized?

A student performed an investigation in which two ivy plants were planted in two separate containers. One of the containers had earthworms mixed in with the soil, and the other container had soil and no earthworms. The plants were given the same amount of water and exposed to the same amount of sunlight. The student observed that after several weeks of growth, the plant exposed to earthworms appeared to be healthier and exhibited more growth. To conclude that the relationship between the plant and the earthworm is an example of mutualism, the student must perform follow-up investigations that do which of the following?

Nudibranchs are marine gastropods that lack shells. Many of these gastropods retain the foul-tasting poisons of their prey and secrete them when threatened. The bright coloration of the nudibranchs warns predators to avoid them. Based on this information, how has adaptation allowed marine gastropods to be successful

without a shell?

The four butterflies in the illustrations represent the offspring in the F₁ generation. Which statement is best supported by the phenotypes of these offspring?