1. The first living organism in a food chain is a) producers
b) primary consumers
c) heterotroph
d) chemosynthesizer

2. The second living organism in a food chain is generally...
a) herbivore
b) carnivore
c) detrivore
d) a photoautotroph

3. Plants use nitrogen to grow and are generally helped by cycling N from the air to the land by bacteria in a process called...
a) nitrogen fixation
b) denitrification
c) decomposition
d) emmigration

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

Ascientist wants to determine the effect of a new type of gasoline. he fillsone car with normal gasoline and another identical car with the new gasoline. which is the control group? a. the new type of gasolineb. the car with the normal gasolinec. the car with the new gasolinethe amount of gasoline usedd. the amount of gasoline used

Aboy with an extra x chromosome probably has which of the following syndromes?