Question

As you travel up a food chain, further from the primary producer, the amount of available energy

Question options:

	increases
	stays the same
	decreases

Question 4

0 / 1 point

The addition of excessive amounts of nutrients to aquatic ecosystems that often results in overgrowth of algae is

___algae blooms___

.

Question 5

0 / 1 point

Check all that apply:

Carbon is essential element for life. As a good heterotroph, you get your carbon directly from

Question options:

	the atmosphere
	consuming organic matter (food)
	water
	magma

Question 6

0 / 1 point

Check all that apply.

Nitrogen is essential nutrient for

Question options:

	proteins
	chlorophyll
	DNA
	carbon dioxide

Question 7

0 / 1 point

use sunlight to synthesize their own food.

Question options:

	autotroph
	photoautotroph
	consumer
	chemoautotroph

Question 8

0 / 1 point

Check all that apply:

Carbon is direcly cycled between plants and the atmosphere via what process(es):

Question options:

	denitrification
	nitrogen fixation
	respiration
	photosynthesis Question 10 0 / 1 point Nitrification is the process in which certain bacteria convert ?   ? to ? ?.   Question options: nitrites to nitrogen gas nitrates to ammonia nitrogen gas to ammonia ammonia to nitrates Question 11 0 / 1 point the fourth most abundant element in living organisms Question options: oxygen hydrogen carbon nitrogen Question 13 0 / 1 point In ______________________ bacteria return nitrogen to the atmosphere by converting nitrates to N2. Question options: Nitrification Respiration Nitrogen-fixing Denitrification

Answer 1

Ans. #3. Decreases.

Only around 10% of the energy of the topic level is available to the next/successive tropic level in the food chain. So, as we go away from the primary producer to top of a food chain, the energy available to the higher tropic levels from adjacent lower tropic level always decreases.

#5. Consuming organic matter. The organic matter from other organisms (plants, fish, egg, etc.) is the only source of carbon for heterotrophs (the organisms which can’t synthesize their own food).

# Being higher animals, humans can’t obtain carbon from water (CO₂ is dissolved in water), magma or the atmosphere (CO₂ as gas).

#6. Proteins, Chlorophyll, DNA

Nitrogen is present in proteins (as -NH₂ group of amino acid), chlorophyll (as porphyrin ring) and DNA (as nitrogenous bases).

#CO₂ does not have any N-atom.

#7. Photoautotrophs

Autotrophs (chemoautotrophs, photoautotrophs) use CO₂ as the source of carbon.

However, photoautotrophs use sunlight as source of energy to assimilate CO₂ into food (say, glucose during photosynthesis) whereas chemoautotrophs derive the energy for synthesizing food from chemical reactions but NOT light.

# Since the terms autotrophs may refer to both chemo- and photoautotrophs, the terms photoautotrophs is most appropriate in this context.

#8. Respiration, Photosynthesis.

During respiration plants release CO2 to atmosphere. During photosynthesis plants absorb CO2 from atmosphere.

# Denitrification and nitrogen fixation cycle nitrogen between organisms and atmosphere.

#10. Ammonia to nitrates.

Nitrification is the process of conversion of ammonia to nitrite and successively to nitrate.

#11. Nitrogen

Most abundant element = Carbon ;          2^nd Most abundant element = Hydrogen

3^rd Most abundant element = Oxygen ; 4^th Most abundant element = Nitrogen

#12. Denitrification

Denitrification is the process of converting nitrates to N₂ gas which is released into atmosphere.

# Nitrification is the process of conversion of ammonia to nitrite and successively to nitrate.

# Respiration releases CO₂ (and, H₂O) into atmosphere.

# Nitrogen fixation converts atmospheric nitrogen into NH₃.