Question

1. marine viruses are harmful to marine ecosystems for all of the following reasons except:

a.) they infect and kill many bacteria & phytoplankton
b.) they carry out nitrogen fixation
c.) they can alter chemical cycles
d.) they can interrupt planktonic food webs

1. an autotrophic bacterium...

a.) uses sunlight to make its own food
b.) uses chemicals like sulfur to make its own food
c.) eats other marine microbes as food
d.) uses carbon dioxide as food

1. a major portion of the free oxygen found in the ocean comes from...

a.) the atmosphere
b.) marine viruses
c.) marine fungi
d.) cyanobacteria

1. chemosynthetic bacteria are usually anaerobic. anaerobic means that these bacteria....

a.) dont like oxygen
b.) dont like carbon dioxide
c.) like to use sunlight as an energy source
d.) like to use chemicals in their food production

1. bacteria that are consumers and decomposers use ______________ to obtain energy.

a.) sunlight
b.) sulfur
c.) carbon dioxide
d.) organic matter

Explanation:

1. Marine viruses are harmful as they infect/kill bacteria/phytoplankton, alter chemical cycles, and interrupt food webs. Nitrogen fixation is a beneficial process (usually by certain bacteria, not a harmful effect of viruses).
2. Autotrophic bacteria make their own food. Options A (photosynthetic autotrophs), B (chemosynthetic autotrophs using sulfur), and D (using carbon dioxide as a carbon source) are ways they make food. Option C is for heterotrophs (not autotrophs).
3. Cyanobacteria (photosynthetic) produce a major portion of ocean's free oxygen. The atmosphere's oxygen dissolved in water is a smaller source. Marine viruses and fungi don't produce significant free oxygen.
4. Anaerobic means doesn't require oxygen (can imply they don't like it as it might be toxic). Option B is about carbon dioxide (not relevant to anaerobic), C is for photosynthetic organisms (not related to anaerobic in this context), D is about chemosynthesis (not directly about oxygen preference).
5. Consumers and decomposers (heterotrophs) use organic matter (from other organisms) for energy. Sunlight is for photosynthetic producers, sulfur for some chemosynthetic bacteria, and carbon dioxide for autotrophs (as a carbon source, not energy source in this context).

Answer:

1. B. They carry out Nitrogen Fixation
2. C. Eats other marine microbes as food
3. D. Cyanobacteria
4. A. Don’t like oxygen
5. D. Organic Matter