JAMB UTME Biology 2015 past questions and answers

1. Organisms use much of the energy for life processes and lose it as heat
2. Energy is converted into new matter that decomposers cannot use
3. Producers absorb all energy before consumers can feed
4. Consumers return all energy to the soil through excretion

Answer: A. Organisms use much of the energy for life processes and lose it as heat

Respiration and other life processes dissipate much energy as heat, leaving less biomass energy for the next trophic level.

1. Many grasses support a few grazing antelopes
2. One large tree supports many insect herbivores
3. Many phytoplankton support fewer zooplankton
4. Many prey animals support fewer predators

Answer: B. One large tree supports many insect herbivores

A single tree may support numerous insects, so the producer count is lower than the primary-consumer count.

1. They convert nitrates in soil into atmospheric nitrogen
2. They release oxygen from nitrates during photosynthesis
3. They fix atmospheric nitrogen into compounds usable by plants
4. They convert plant proteins directly into atmospheric nitrogen

Answer: C. They fix atmospheric nitrogen into compounds usable by plants

Rhizobium in root nodules fixes atmospheric nitrogen into nitrogen compounds that can enter biological systems.

1. Spraying a field with a synthetic insecticide
2. Removing weeds by hand
3. Planting a resistant crop variety
4. Releasing a natural predator of the pest into the field

Answer: D. Releasing a natural predator of the pest into the field

Biological control reduces a pest population by using its natural enemy, such as a predator or parasite.

1. 4 snails per m^2
2. 12 snails per m^2
3. 36 snails per m^2
4. 60 snails per m^2

Answer: A. 4 snails per m^2

Population density is 48 divided by 12, which equals 4 snails per square metre.