What is the main purpose of scientific models?
a. the main purpose of models is to have a physical object to which to refer.
b. the main purpose of models is to represent observations.
c. the main purpose of models is to study systems that no longer exist.
d. the main purpose of models is to gain a better understanding of the world.

Consider an organism that is eukaryotic, found in both unicellular and multicellular forms, may resemble a plant but is not photosynthetic, has chitin in its cell walls, and absorbs organic nutrients from decomposing material in the environment. this organism would be classified as which of the following types of organisms? a. fungib. protozoac. bacteriad. archaea

Identify the type of energy used in each action. the flexing of an arm muscle: a signal transduction process by a neuron: a ball at the top of a hill: 1. electrical energy 2. mechanical energy 3. gravitational potential energy

Use this dichotomous key for insect identification to identify the insect shown. 1. a. insect has one pair of wings. order diptera b. insect has two pairs of wings. go to #2 2. a. front wings thicker in texture than hind wings go to #3. b. front and hind wings are same texture throughout. go to #4 3. a. front wings are short order dermaptera b. front wings cover entire abdomen order coleoptera 4. a. wings with scale on all parts of their area. order lepidoptera b. wings without scales go to #5. 5. a. hind wings smaller than front wings. order ephemeroptera b. front and hind wings nearly equal in size. order odonata the insect pictured is in the order diptera. ephemeroptera. coleoptera. odonata.