In nature, plants and animals are perpetually engaged in mutualism because

A. they are rivals

B. all animals rely on food produced by plants

C. they utilize respiratory wastes of each other

D. they are neighbours

In an experiment to determine the percentage of humus and water in a soil sample, the following results were obtained
Weight of the evaporating basin alone = 80.5g
Weight of basin and soil = 101.5g
Weight after drying the soil in the oven = 99.0g
Weight of basin and roasted soil = 95.5g
The percentage of humus in the soil sample is

A. 16.7%

B. 17.6%

C. 26.7%

D. 16.2%

An example of a filter -feeding animal is

A. shark

B. butterfly

C. whale

D. mosquito

Which of the following is a feature of the population pyramid of a developing country?

A. long lifespan

B. low birth rate

C. low death rate

D. short lifespan

The interaction of a community of organisms with its abiotic environment constitutes

A. niche

B. a food chain

C. an ecosystem

D. a mirohabitat

The vector of the malaria parasite is

A. female Aedes mosquito

B. female Anopheles mosquito

C. male Culex mosquito

D. female Culex mosquito

Which of the following instruments is used to measure relative humidity?

A. Hydrometer

B. Thermometer

C. Hygrometer

D. Anemometer

Exo-erythrocytic phase of the life cycle of malaria parasite occurs in the

A. liver of humans

B. reticuloendothelial cells of humans

C. Malphigian tubules of mosquito

D. brain of humans

Habitats are generally classified into

A. biotic and abiotic

B. aquatic and terrestrial

C. aboreal and marine biomes

D. microhabitats and macrohabitats

Drancunculiasis can be contacted through

A. eating contaminated food

B. drinking contaminated water

C. bathing in contaminated water

D. bites of blackfly