The atmosphere traps a part of the sun’s heat that is reflected from earth’s surface. this effect, called the greenhouse effect, is primarily responsible for the moderate average temperatures on earth. what component of the atmosphere causes this to occur? a) the ozone layer b) the layers of the atmosphere c) gases such as oxygen and nitrogen d) gases such as carbon dioxide and methane 32) primary succession begins after a a) tornado. b) hurricane. c) lava flow. d) forest fire. 33) during the process of ecological succession a) many new species of organisms evolve rapidly. b) the number of species in the community decreases. c) the amount of biomass in the community stays constant. d) an increasing number of resources and niches become available for animals. 34) the zebra mussel is a shellfish native to europe. during the early 1900's, it was accidentally brought to the united states in the ballast of a ship traveling to the great lakes. it has no predators in the great lakes. what impact are zebra mussels likely to have on food chains in the great lakes? a) they will have no real effects on the food chain, since they are from europe. b) they will compete with native shellfish and clams and hurt their populations. c) they will allow fish populations to expand, because they will be used as food. d) they will cause the entire food chain to crash, since they do not fit into the original food chain. 35) why are coral reefs home to a huge diverse variety of species? a) coral reefs have all the factors necessary to support plants, predators, and prey. b) coral reefs keep predators, such as sharks, away providing a safe habitat for fish. c) the presence of sunlight keeps animals away, allowing a variety of plants to thrive. d) as deep ocean habitats, coral reefs provide a safe habitat for a variety of species.

The greenhouse effect occurs with the gases such as carbon dioxide and methane.

The UV radiations from sun reaches earth’s surface through the atmosphere. The earth’s surface absorbs some of the heat and emits the heat energy. This emitted heat energy is blocked by greenhouse gases. The major greenhouse gases includes carbon dioxide, water vapor, methane, nitrous oxide, chlorofluorocarbon, hydro fluorocarbon, and ozone.

These gases take a major toll in global climates (increased temperature which lead to melting of ice capes) and oceans lives (ocean acidification and coral bleaching). This effect is reduced by growing plants which helps to absorb major greenhouse gases.

The primary succession begins after lava flow.

The ecological succession refers to the process in which animals and plants of rare species occupies a barren land and makes a lead to change ecological community. This changes occur until the ecosystem continues to survive itself.  

The primary succession is a type of ecological succession. In this process, the occupation of the plants and animals take place in a location which is previously not occupied by any plants and animals. The location on which primary succession takes place includes area with newly exposed rocks and area which is exposed to lava flow previously.

The other factors given in the options are related to secondary succession.

During ecological succession, the resources increase and an animals’ found their niche.

The ecological succession refers to a process in which an ecosystem evolve to thrive in period of time. This process does not take place rapidly.

The number of species will start to increase, this process of progression differs according to the type of the ecological succession.

The biomass refers the quantity of organisms or biotic factor in a volume or area. So, when the ecological succession takes place, the biomass starts to increase where it will not remain constant for a long period of time.

The ecological succession leads to increase in the resources for the animals and plants. The area where the succession takes place becomes home for the animals and plants by providing them shelter and food. It provides niches (role/position) for the animals in that ecological community.

The zebra mussels impacts the food chain by competing with the native shellfish and decreasing their population. They also lead to the population growth of some fishes due to their habits.

For this question, option (B) and (C) is suitable answer. But option (B) is more apt answer.

Description on zebra mussels:

The zebra mussels are mussels which grow in freshwater. These are invasive species which are non-native and cause damage to environment and lives of humans and animals. These species are filter feeding organisms which feed on the material suspended on the water (pollutants).

The explanation for option (B):

Zebra mussels widely affect the species which have similar food habit. These species led to population reduction of zooplanktons and juvenile fishes.

The explanation for option (C):

Zebra mussels cleaned all the waters by their feeding and led to clear water. This increased the growth of the algae and the invertebrates depending on the algae which in turn led to the development of the fishes feeding on those tiny organisms. The population of the fish named smallmouth bass is increased due to this process.

Conclusion:

There is major shift in the population of the water organisms due the zebra mussels. Wide range of steps are taken to reduce the growth of these mussels because they led to water clogging and other damages to ships and underwater systems.

The negative effects of the zebra mussels are more than their positive effects. So, the correct answer for this question is option (B) is more apt answer.

The coral reef is home for wide range of species because they have all factors necessary to support plants, predators, and prey.

The coral reefs are underwater ecosystem where the coral polyps build reefs. These reefs not only provide ecosystem services but also help many water species.

81 is a composite number.