Which of the following practices does not contribute to the preservation and improvement of the environment?
- A. Pollution reduction
- B. Material recycling
- C. Reforestation
- D. Overgrazing
A species whose populations has become so small that it may become extinct if not protected is a/an
- A. special species
- B. dangerous species
- C. endangered species
- D. important species
Which of the following factors will most likely lead to overcrowding within a population?
- A. Absence of predators
- B. Emigration
- C. Food shortage
- D. Absence of territorial behaviour
In ecological succession, since Iichens grow on bare rock, they are considered to be
- A. primary consumers
- B. pioneer organisms
- C. climax organisms
- D. producers
Population growth rate may be defined as the
- A. ortality rate per unit area over a period
- B. number of times an organism occurs within a given period
- C. number of a particular species per unit area
- D. net rate of natality and mortality in the habitat over a period.
The following habitats can be used in the study of succession except
- A. savanna grassland
- B. abandoned farmland.
- C. a pond
- D. a well cultivated land
Which of the following features is not an adaptation of plants to aquatic habitat?
- A. Breathing roots for entry of air
- B. Flowers raised above water for the purpose of pollination
- C. Spongy tissues containing gases for buoyancy
- D. Hairy structures on the leaves to reduce water loss
Most tropical plants shed their leaves during dry weather conditions in order to
- A. reduce their growth rate.
- B. conserve water
- C. reduce competition
- D. minimize the rate of photosynthesis
which of the following organisms does not show colour adaptation to its environment?
- A. Chameleon
- B. Earthworm
- C. Fish
- D. Toad
Food chains are relatively short because
- A. of energy recycling in the ecosystem
- B. energy gain at each trophic level is high.
- C. of energy loss at each trophic level
- D. energy flow in an ecosystem is uni-directional.
P → Q → R → S → T
Which of the following statements best describes the organism designated R? It
- A. feeds on S
- B. is a primary consumer
- C. is a producer as well as a consumer
- D. is a secondary consumer
P → Q → R → S → T
he organism designated P in the food chain above is normally sustained by energy from
- A. sunlight
- B. carbohydrates
- C. green plants
- D. mineral salts.
Which of the following organisms is a primary consumer?
- A. Dog
- B. Sheep
- C. Grass
- D. Fungus
Which of the following statements is true about sandy soil? It
- A. has limited air space
- B. is light and easy to dig
- C. drains slowly
- D. is heavy and poorly aerated
Which of the following instruments is used to estimate the number of plants in a habitat?
- A. Pooter
- B. Pitfall trap
- C. Quadrat
- D. Sweep net
What is the critical limiting factor for plants below the photic zone is an aquatic ecosystem?
- A. Availability of nutrients
- B. Availability of water
- C. Intensity of light
- D. Carbon dioxide concentration
Which of the following statements about ecosystems is false?
- A. All the energy entering the ecosystem is passed on to decomposers
- B. The primary producers provide energy for herbivores and carnivores
- C. Ecosystems must start with the capture of energy by autotrophs
- D. Energy transfer from one trophic level to the other is not 100% efficient.
Which of the following organisms is an endoparasite?
- A. Mice
- B. Mosquito
- C. Ascaris
- D. Dodder
An organism whose source of carbon is inorganic is likely to be a/an
- A. heterotrophic organism
- B. autotrophic organism
- C. symbiotic organism
- D. parasitic organism
Pepsin is secreted as an inactive precursor called pepsinogen because
- A. pepsin as an enzyme is quickly destroyed by the alkaline food from the mouth
- B. all digestive enzymes pass through a precursor stage
- C. pepsin is a proteolytic enzyme and might attack the stomach tissues
- D. pepsin is not required in large quantities
Which of the following treatments would increase the rate of transpiration in a potted plant?
- A. Placing it in a cold room
- B. Placing it under a fan in a room
- C. Putting it in a cupboard
- D. Smearing grease on the lower surface of the leaves