Which of the following is not an abiotic factor that influences the distribution of organisms?Availability of foodWaterAtmospheric gasesTemperature2Which of the following is an ‘indicator species’ of oxygenated water?Mayfly larvaeLichenRed-tailed maggotSludgeworms3Why does the bright red colour of sludgeworms mean they can thrive in water containing low levels of oxygen?It attracts matesIt warns off predatorsIt indicates a high concentration of haemoglobinIt provides camouflage4Lichens are plant-like organisms that grow in exposed places such as rocks or tree bark. If few or no lichens are growing in a specific area, what might this indicate? The air is pollutedA new pathogen has been introducedA new predator has been introducedThe air is clean

The abiotic factor that does not influence the distribution of organisms from the options provided is the "Availability of food". This is because food is a biotic factor, meaning it is living or comes from living organisms. Abiotic factors are non-living physical and chemical elements in the ecosystem.

The 'indicator species' of oxygenated water from the options provided is the "Mayfly larvae". Mayfly larvae are sensitive to pollution and low oxygen levels, so their presence often indicates clean, oxygen-rich water.

The bright red colour of sludgeworms means they can thrive in water containing low levels of oxygen because "It indicates a high concentration of haemoglobin". Haemoglobin is a protein in blood that binds to oxygen; a high concentration of it allows the sludgeworms to survive in low-oxygen environments.

If few or no lichens are growing in a specific area, this might indicate that "The air is polluted". Lichens are sensitive to air pollution, especially sulfur dioxide. A lack of lichens in an area can be a sign of high levels of air pollution.