Which option describes how the amount of land used for agriculture has changed overtime 1. Slow increase until 1800s and then a very sharp increase between 1800 and today.
2.steady increase throughout known history
3. Almost no change until 1800s and then a steady increase between 1800 and today
4. Steady increase until the late 1990s then a slow decline

The deserts of the sahara and australia are associated with

1. environmental factors, such as ph and temperature, can affect the function of an enzyme. a. true b. false 2. which of the following is an organic molecules (ex. vitamins) that an enzyme? a. coenzyme b. product c. active site d. substrate 3. how do enzymes effect the speed of a chemical reaction? a. they speed it up b. they slow it down c. they have no effect on the speed of a reaction 4. during a chemical reaction, an enzyme is used up so that it can only be used one time. a. true b. false 5. which of the following results from a chemical reaction that is catalyzed by an enzymes? a. active site b. product c. substrate d. coenzyme

Which statement about the immune system is false? a. lymphocytes reduce inflammation, b. b cells remember specific pathogens. c. most white blood cells kill bacteria d. white blood cells are made in lymph nodes.