Which of the following human traits in a class of school children may give an approximate normal distribution curve when the variation is plotted?
- A. Blood groups
- B. Ear shapes
- C. Sex distribution
- D. Heights
Which of the following characters is not an example of discontinuous variation?
- A. Skin color
- B. Fingerprint
- C. Ability to roll tongue
- D. Sex type
Which of the following statements about phenylthiocarbamide (PTC) is not correct?
- A. Some people BHG the taste of PTC to be bitter
- B. Others find this substance to be tasteless
- C. Ability to taste this chemical is inheritable
- D. Ability to taste the chemical is hot inheritable
Which of the following substances is not recycled in an ecosystem?
- A. Carbon
- B. Energy
- C. Water
- D. Nitrogen
Conservation may be promote by
- A. encouraging tree planting
- B. systematic deforestation
- C. overgrazing of pastures
- D. unabated bush timing
To avoid over fishing in a lake, the following measures may be helpful except
- A. limiting fishing periods
- B. regulating the size of nets
- C. fishing throughout the year
- D. fish breeding exercise
Many diseases caused by bacteria can be treated and cured by using
- A. antiseptics
- B. antibiotics
- C. antigens
- D. antibodies
Which of the following activities constitutes biological control?
- A. A small bony fish transported on the back of a shark
- B. Adding manure to crops in a garden
- C. Tilapia feeding on the larvae and pupae of mosquito
- D. A vulture feeding on the carcass of a goat
A vaccine is introduced into a person‘s body to
- A. destroy all disease-causing organisms in the body
- B. stimulate the body to produce antibodies
- C. enhance the production of red blood cells
- D. isolate disease-causing pathogens from the blood.
The following observations concerning succession are true except that the
- A. pioneer community has fewer species
- B. middle stages communities are most diverse
- C. max community has the greatest number of species
- D. total biomass of the community increases as succession progresses
The effects of environmental degradation caused by human activities can be controlled by e following measures except
- A. reclaiming the land
- B. converting mining pits into fish ponds
- C. resettling indigenous inhabitants
- D. educating people
The speed of the flow of water in a river is faster in the middle than along the banks due to
- A. differences to turbidity at different parts of the river
- B. the abundance of fishes and other organisms along the bank
- C. reduced force of gravity in the middle portion of the river
- D. resistance offered by the wall of the banks.
Shrubs do not survive on newly weathered soils because
- A. the top soil is shallow
- B. drainage on such soil is poor
- C. humus is absent from the soil
- D. the soil tends to be sandy
Pond weeds normally lack thick layers of cuticle because
- A. their system of photosynthesis is not efficient
- B. there is no danger of becoming desiccated
- C. their leaves are either dissected or n bon-shaped
- D. there are numerous stoma a on their upper epidermis
Which of the following statements about the transfer of energy in the ecosystem is correct?
- A. energy increases at high trophic levels
- B. More organisms can be supported at higher levels
- C. There are fewer organisms at top tropic levels
- D. Energy is lost at each trophic level
What would be the effect of taking the lion out of the web?
- A. The number of organisms at each trophic level would increase
- B. Man would occupy the apex of the web
- C. There would be more rabbit in the web
- D. The energy reaching the remaining trophic would be increase
Tertiary consumers within the web are
- A. cat and lion only
- B. Man and lion only
- C. man and cat only
- D. man, cat and lion
Which of the following instruments is used to measure wind speed?
- A. Thermometer
- B. Barometer
- C. Hygrometer
- D. Anemometer
Which of the following physical actors is likely to affect the distribution of plants in a pond?
- A. light
- B. Humid
- C. Wind
- D. Temperature
A community is best described as
- A. living things in a habitat interacting with the non-living part of the environment
- B. the total number of individuals of one species of organisms living in a particular habitat
- C. populations of different species living together and interacting with each other in one habitat
- D. the individuals of a particular group living together in an area and sharing the same resources
The impedance of the concentration of chloroplast in the palisade layer of the leaf is for maximum exposure to
- A. carbon dioxide
- B. light
- C. water
- D. oxygen