A vaccine is introduced into a person‘s body to
destroy all disease-causing organisms in the body
stimulate the body to produce antibodies
enhance the production of red blood cells
isolate disease-causing pathogens from the blood
Correct answer is B
No explanation has been provided for this answer.
The following observations concerning succession are true except that the
pioneer community has fewer species
middle stages communities are most diverse
max community has the greatest number of species
total biomass of the community increases as succession progresses
Correct answer is C
No explanation has been provided for this answer.
reclaiming the land
converting mining pits into fish ponds
resettling indigenous inhabitants
educating people
Correct answer is B
No explanation has been provided for this answer.
The speed of the flow of water in a river is faster in the middle than along the banks due to
differences to turbidity at different parts of the river
the abundance of fishes and other organisms along the bank
reduced force of gravity in the middle portion of the river
resistance offered by the wall of the banks
Correct answer is D
No explanation has been provided for this answer.
Shrubs do not survive on newly weathered soils because
the top soil is shallow
drainage on such soil is poor
humus is absent from the soil
the soil tends to be sandy
Correct answer is A
No explanation has been provided for this answer.