Jon is researching the oxygenation of Earth’s atmosphere. Which unicellular organism do biologists consider to be the main contributor to that process?

A. paramecia
B. amoebae
C. dinoflagellate
D. cyanobacteria

Answer is D. cyanobacteria

Select the correct answer. in the image, if the washcloth represents consumed food, which organ of the digestive system correctly represents the action performed by the hands? hands squeezing water from a washcloth a. esophagus b. large intestine c. liver d. mouth

To store strawberries in sugar syrup, lucy placed them in a jar and covered them with sugar but did not add any water. do you think syrup will be formed? justify. a. no. since water is not added, there cannot be any syrup formation. b. no. the higher concentration of sugar on the outside will cause the water from the sugar to diffuse in the strawberry cells causing them to swell without formation of any syrup. c. yes. the higher concentration of sugar on the outside will cause the water from the strawberry to diffuse out resulting in syrup formation. d. yes. the sugar will melt over time and form the syrup.

Which line in the graph above best illustrates an effect of the carbon dioxide level in the blood on breathing rate before, during and after a period of exercise? 1.b,2.c,3.a,4.d