Correct Answer: B. conserve water

Correct Answer: D) bush fallowing

Explanation

The question is asking about a farming practice where a land that has been used for cultivation is left unused for some years before it is used again. This practice is called bush fallowing. It is a way of allowing the land to regain its fertility and improve crop yield. Crop rotation is a farming practice where different crops are planted in a particular order on the same land over a period of time to maintain soil fertility and reduce pest and disease build-up. Continuous cropping is a practice where crops are planted on the same land repeatedly without allowing the soil to rest and regain its nutrients. This practice can lead to soil depletion and may result in low crop yield. Mono cropping, on the other hand, is a farming practice where only one type of crop is grown repeatedly on the same land. This practice can lead to soil depletion, pest and disease build-up and reduced crop yield. In summary, the farming practice where an exhausted land is left unused for some years before cultivation is called bush fallowing. This practice helps to improve soil fertility and crop yield. Crop rotation, continuous cropping and mono cropping are other farming practices used to maintain soil fertility and improve crop yield.

Correct Answer: C) Euglena

Explanation

The question is asking which organism has a single cell that can perform all the functions of active movement, nutrition, growth, excretion, and photosynthesis. The options are Paramecium, Amoeba, Euglena, and Hydra. Out of these options, the correct answer is Euglena. Euglena is a unicellular organism that has a flagellum which it uses for active movement. It also has chloroplasts which are responsible for photosynthesis, and it can absorb nutrients from its environment for nutrition. Euglena is also capable of excreting waste products through an organelle called the contractile vacuole. Finally, it can undergo cell division to grow and reproduce. It is important to note that while Paramecium and Amoeba are also unicellular organisms, they do not have chloroplasts and cannot perform photosynthesis. Hydra, on the other hand, is a multicellular organism and does not have a single cell that can perform all the functions listed in the question. In summary, Euglena is the correct answer because it is a unicellular organism that can perform all the functions of active movement, nutrition, growth, excretion, and photosynthesis.

Explanation

Protective adaptations used by animals against predation

(i) Mechanical protection like the hard outer covering/ shell; e.g. giant snail/tortoise/oysters/barnacles/battery of spines in porcupine/sea urchin

(ii) Chemical protection in the form of poisonous secretions of skin glands; e.g. toad

(iii) Concealing colouration/cryptic adaptation/a close matching in appearance of the animal to its background; e.g. chameleon/praying mantis/green mamba

(iv) Specialised toxic glands/hairs linked to toxic glands/hairs that penetrate skin of predators/toxin secreted to cause intense irritation; e.g. larvae of Lepidoptera

(v) Mimicry of objects such as leaves or twigs; e.g. Praying mantis/stick insect/ moths

(vi) Rolling the body into a ball; e.g. pangolin/millipede/porcupine

(vii) Fast movement to escape from enemies; e.g. antelopes/deers

(viii) Secretion of offensive smell; e.g. shrews/zonocerus

(ix) Stings/injection of painful chemicals; e.g. bees/wasps/scorpions/electric fish

(x) Offensive structures of horns/hooves; e.g. antelopes/gazel/buffalos

(xi) Movement in groups to frighten predators; e.g. monkeys/baboons/small angulates

(xii) Detachment/dropping of parts of the body to escape; e.g. lizards/wall geckos

(xiii) Secretion of ink/coloured substance to impair vision of predator/create a screen e.g. squid

(xiv) Inflation of the body to frighten predator; e.g. chameleon/octopus/cats

(xv) And any other correct adaptive features and correct examples

(b)(i) Pollution

(a) The introduction of materials/ energy into the environment by humans (directly or indirectly)

(b) at such levels/concentration that affect biotic communities adversely thereby causing harm

(ii)Activities of humans which cause pollution

(a) Dumping of domestic/ farm refuse

(b) Release of chemicals from mines

(c) Misapplication of agro chemicals/fertilizers

(d) Spraying of pesticides and herbicides

(e) Dumping of broken bottles/glasses/ enamel wares

(f) Dumping of plastics

(g) Dumping of scrap metals

(h) Spillage of crude oil from pipelines/tankers

(i) Dumping of untreated sewage

(j) Effluent from factories/breweries/laboratories (i) Any other correct human activity

Correct Answer: A. negative phototaxism

Correct Answer: D. Producers

Correct Answer: C. flooding and earthquake

Correct Answer: C. cerebrum

Correct Answer: C. organisms that are constantly regenerating themselves

Correct Answer: A) chyme

Explanation

After food is swallowed, it travels down the esophagus and enters the stomach. In the stomach, the food is mixed with digestive juices and broken down into smaller particles. The resulting mixture is called chyme. Chyme is a partially digested, semi-liquid substance that is ready to leave the stomach and enter the small intestine for further digestion and absorption of nutrients. Option A, chyme, is the correct answer to the question. Options B, C, and D are incorrect. Curb and paste are not terms used to describe partially digested food, while glycogen is a form of glucose stored in the liver and muscles. It is important to note that the stomach plays a crucial role in the digestive system. It not only breaks down food into chyme but also kills harmful bacteria and viruses that may be present in the food. The stomach also releases hormones and signals to regulate the digestive process and appetite.