Phytoplanktons (algae) of oceans are the highest producers of organic matter.

Correct Option: D

Phytoplanktons (algae) of oceans are the highest producers of organic matter.

German biologist Ernst Haeckel coined the term 'ecology', the study of interrelationship between organisms and their environment. Ecosystem, consist of different communities of organism and the physical environment with which they interact. Phytogeography is the study of geographic distribution of plants species on earth.

Correct Option: A

German biologist Ernst Haeckel coined the term 'ecology', the study of interrelationship between organisms and their environment. Ecosystem, consist of different communities of organism and the physical environment with which they interact. Phytogeography is the study of geographic distribution of plants species on earth.

Soil is the uppermost weathered layer or earth's crust and is composed of minerals and partly decomposed organic matter. Pedologist is a scientist who studies origin, composition and distribution of soil and the materials from which the soil is made.

Correct Option: B

Soil is the uppermost weathered layer or earth's crust and is composed of minerals and partly decomposed organic matter. Pedologist is a scientist who studies origin, composition and distribution of soil and the materials from which the soil is made.

Decomposers act on dead bodies converting complex organic constituents into simpler soluble form. They obtain their energy from dead organisms. Decomposers themselves are organisms (often fungi, earthworms, or bacteria) that break down organic materials to gain nutrients and energy. Decomposers accelerate the natural process of decomposition. They supply the required nutrients for other trophic levels. The fungi found on the tree are decomposers. When an organism dies, it leaves behind nutrients that are tightly bound together. A scavenger might eat the carcass, but its feces would still contain a considerable amount of unused energy and nutrients. Decomposers will later induce further breakdown. This last step releases raw nutrients (such as nitrogen, phosphorus and magnesium) in a form usable to plants, which quickly incorporates the chemicals into their own cells. This process greatly increases the nutrient-load of an ecosystem, in turn allowing for greater biodiversity.

Correct Option: D

Decomposers act on dead bodies converting complex organic constituents into simpler soluble form. They obtain their energy from dead organisms. Decomposers themselves are organisms (often fungi, earthworms, or bacteria) that break down organic materials to gain nutrients and energy. Decomposers accelerate the natural process of decomposition. They supply the required nutrients for other trophic levels. The fungi found on the tree are decomposers. When an organism dies, it leaves behind nutrients that are tightly bound together. A scavenger might eat the carcass, but its feces would still contain a considerable amount of unused energy and nutrients. Decomposers will later induce further breakdown. This last step releases raw nutrients (such as nitrogen, phosphorus and magnesium) in a form usable to plants, which quickly incorporates the chemicals into their own cells. This process greatly increases the nutrient-load of an ecosystem, in turn allowing for greater biodiversity.

Plankton ? Organisms passively floating in upper water.
Nekton ? Actively swimming
Benthos ? Lead sedentary life upon the sea bottom

Correct Option: A

Plankton ? Organisms passively floating in upper water.
Nekton ? Actively swimming
Benthos ? Lead sedentary life upon the sea bottom