Correct Answer: (2) Organism 3 helps recycle materials.

Organism 3 is a mushroom (a fungus) which is a decomposer. Decomposers re organisms that absorb nutrients from nonliving organic materials such as corpses, fallen plant material and the wastes of living organism, and transform them into inorganic forms

Incorrect Answers:

Organism 2 is a grass, which is autotrophic. Autotrophs obtain organic food molecules without eating organisms. They use energy from the sun of from the oxidation of inorganic substances to make organic molecules from inorganic ones.

Organism 4 is a grasshopper. It feeds on plants, therefore it is heterotrophic. Heterotrophs obtain organic food molecules by eating other organism or their by-products.

Organism 5 is a rat, while organism 1 is a snake. Rats cannot eat snakes, but snakes can eat rats to obtain energy.

Correct Answer: (4) autotrophic nutrition

Autotrops are organisms that obtain organic food molecules without eating other organisms. Autotrophs use energy from the sun by the process of photosynthesis. During photosynthesis, solar energy drives the conversion of carbon dioxide and water into glucose and oxygen.

Incorrect Answers:

During cellular respiration, oxygen is consumed as a reactant along with glucose, while carbon dioxide and ATP re the products.

Asexual reproduction is not driven by carbon dioxide.

Active transport is the movement of a substance across a biological membrane against its concentration gradient with the help of energy input (ATP) and specific transport proteins. Carbon dioxide is not directly involved in active transport.

Correct Answer: (3) beneficial to both species

This is called mutualism. Both the symbiont and the host benefit from each other. The unicellular organism inhabits the intestine of the termite, while the termite eats the products of the unicellular organism.

Incorrect Answer:

No harm was elucidated from the relationship of the two organisms.

Parasitism is the symbiotic relationship between an organism that lives inside another organism. However, in this case, the host is consumed or harmed in the process.

Predation refers to interspecific interaction where a predator (an organism that pursuits other organisms) eats its prey (the organism that is assaulted).

Correct Answer: (3) Certain herbivores will exceed carrying capacity

Carrying capacity refers to thee maximum population size that can be supported by the available resources. Carnivorous predators feed on herbivores or other carnivores. Since the predators of the herbivores are removed, the population of the herbivores will increase.

Incorrect Answers:

The natural prey will not die because they are not preyed upon due to the absence of their predators.

Plants are the producers in the food chain. They are not directly involved with the carnivorous predators because they are not part of their food preference.

Decomposers cannot fill the predator niche because they have different habitat and function in the community.

Correct Answer: (4) succession

Ecological succession is the transition in the species composition of a biological community, often following ecological disturbance of the community. This illustration is particularly called primary succession wherein a biological community was established in an area virtually barren of life.

Incorrect Answers:

Replication is the process of forming messenger RNAs prior to protein synthesis.

Recycling is the process of using a material which was previously used for a different purpose or function.

Feedback is a primary mechanism of homeostasis, whereby a change in  physiological variable that is being monitored triggers a response.

Correct Answer: (3) predators

Predators are organisms that feed on other organisms in order to survive. They have lower population size because their population depends on the organisms A.

Incorrect  Answers:

Scavengers are organisms that search for useful materials like food from the wastes of another organisms.

Autotrophs are organisms that survive by producing their own food through photosynthesis.

Parasites are organisms that live inside the body of another organism in order to survive.

Correct Answer:

Heterotrophs are organisms that obtain organic food molecules by eating other organisms or their by-products. This food web is composed of three trophic levels-producers, primary consumer and the secondary consumer. Both consumers are considered heterotrophs. Organisms B feed on organisms A. Organism A could be the grasshopper, rabbit or deer, all of which are herbivorous.

The lowest level of the energy pyramid belongs to the producers. They have the largest amount of energy contained, which is transferred (some are lost as heat) to the following levels. Grasses and trees are found at level X. They can produce their own food by converting carbon dioxide and water into glucose and oxygen by the use of solar energy.

The production of the field decreased because of the low soil nutrient content of the field. There are two reasons why the soil content of the cornfield is low. First, the farmer failed to alternate the crops produced in his field. He just used one type of crop, therefore, the same type of nutrients were used up from his field. He should have planted legumes like peanuts after harvesting corn so that the soil will recover the nutrients with the help of the nitrogen-fixing bacteria found in the roots of legumes. Second, the dead corn stalks were removed from the field. The decomposers act on detritus to convert them into organic nutrients. Since there are no dead materials to be broken down by the decomposers, the soil remained lacking in nutrients which are very vital in the growth and production of the corn.