Which domestic sewage mixes with river water
small animals like rats will die after drinking river water
the increased microbial activity releases micronutrients such as iron
the increased microbial activity uses up dissolved oxygen
the increased microbial activity uses up dissolved oxygen
C.
the increased microbial activity uses up dissolved oxygen
Domestic sewage consists a lot of degradable organic matter. When this sewage is released into river water, it will result in an increase of Biochemical oxygen demand (BOD) and decrease the amount of dissolved oxygen due to the decomposing activity of microbes.
The breakdown of detritus into smaller particles by earthworm is a process called
humification
fragmentation
mineralisation
mineralisation
B.
fragmentation
The breakdown of detritus (dead remains of plants and animals) into smaller particles by detrivores like earth worm is called fragmentation. it is the first step in the process of decomposition.
Study the four statements (1-4) given below and select the two correct one out of them.
1. A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers
2.Predator starfish pisaster helps in maintaining species diversity of some invertebrates
3.Predators ultimately lead to the extinction of prey species
4.Production of chemicals such as nicotine, strychnine by the plants are metabolic disorders
The two correct statements are
(2) and (3)
(3) and (4)
(1) and (4)
(1) and (4)
D.
(1) and (4)
Both lion (carnivore) and sparrow (herbivore) and consumers. The Asteroidea occupy several important roles throughout ecology and biology. Sea stars, such as Ochre star (Pisaster ochraceous) have become widely known as the example of the keystone species concept in ecology. Most species are generalist predators, eating molluscs such as clams, oysters, etc.
An imporved variety of trasgenic basmati rice
does not require chemical fertilisers and growth hormones
gives high yield nd is rich in vitamin-A
is completely resistant to all insect pests and diseases of paddy
is completely resistant to all insect pests and diseases of paddy
B.
gives high yield nd is rich in vitamin-A
Golden rice is a variety of Oryza sativa produced through genetic engineering to biosynthesize beta- carotene, a precursor of pro-vitamin-A in the edible parts of rice. The research that led to golden rice has been bred to be especially. disease- resistant, resulting in better crop yields.
The biomass available for consumption by the herbivores the decomposers is called
net primary productivity
secondary productivity
standing crop
standing crop
A.
net primary productivity
Net Primary productivity (NPP) is the weight of organic matter stored by producers in a unit area/ volume per unit time.NPP is equal to the rate of organic matter created by photosynthesis minus the rate of respiration and other loses. Stored biomass is transferred from one trophic level to another trophic level. Secondary productivity is the rate of energy storage at consumers levels-herbivores, carnivorous and decomposers.
Gross Primary productivity (GPP) is referred as total rate of photosynthesis including the organic matter used up in respiration during the measurement period.