Living Things in the Biosphere

Which of the following is a compound that is important for life processes in cells?

• gold

• water

• nitrogen

• hydrogen

Katya listed major questions that scientists try to answer when they classify organisms. Her list included the following questions: How many living things are there? What are the characteristics that define living things? What additional question would be best for Katya to add to her list about classification?

• How are living things related?

• How do living things get energy?

• What do living things need to survive?

• Where do living things make their home?

Which of the following statements correctly identifies the general characteristics of organisms in a domain?

• Domain Eukarya includes single-celled organisms that lack nuclei.

• Domain Bacteria includes multicellular organisms that make their own food.

• Domain Archaea includes single-celled organisms that can be found in hot springs and thermal vents.

• Domain Protista includes single-celled and simple multicellular organisms that have plantlike or animal-like characteristics.

During a laboratory project, Sunita and William use a dichotomous key to identify different insects. The dichotomous key and one of the insects they need to identify are shown in the following figure. In what step of the dichotomous key will Sunita and William identify the insect?

• step 1

• step 2

• step 5

• step 6

During an experiment, India examines prepared slides that her teacher has given her. One of the slides shows a single-celled organism that lives in soil. It has a nucleus and several internal structures. To which domain does the organism likely belong?

Which of the following statements correctly describes a kingdom of Domain Eukarya?

• Kingdom Protista includes single-celled organisms that lack nuclei.

• Kingdom Plantae includes multicellular organisms that can move independently.

• Kingdom Animalia includes multicellular organisms that make their own food.

• Kingdom Fungi includes organisms that get energy by decomposing materials in their environment.

A science class is studying an organism. Using a microscope, the class observed that the cells have nuclei and chloroplasts. In which domain would the organism most likely be classified?

Which of the following methods would be least helpful to a scientist in determining the relatedness of two types of animals?

• comparing the diets of the two animals

• comparing the DNA of the two animals

• comparing the physical characteristics of the two animals

• comparing the development patterns of the two animals

A branching diagram uses shared characteristics to classify organisms. On a branching diagram that compares the major kingdoms of Domain Eukarya, what label might appear to differentiate animals from organisms in the other kingdoms?

• single-celled, make own food

• multicellular, make own food

• multicellular, move independently

• release digestive juices into surroundings

Viruses, bacteria, fungi, and parasites can all be pathogens that may pose a threat to human health. What is a pathogen?