Life in the Dirt: Soil Formation Biology Quiz

If a plant is a living thing, then its remains are organic; if these remains stay in the soil, then they provide the base for organic soil matter.

If microbes process matter, then they release nutrients and toxins; if they produce sticky substances, then they bind soil; thus all roles apply.

If the top layer receives falling leaves and dead bugs, then it has the most organic matter; if humus is dark, then that layer must be the darkest.

If lichens produce acidic chemicals, then the chemicals react with rock; if the rock reacts, then it dissolves into soil minerals.

If water moves downward through soil, then it carries dissolved minerals; if minerals are carried away from the root zone, then it is leaching.

If animal burrows create holes, then water enters the ground instead of running off; if runoff is reduced, then less soil is washed away.

If organisms breathe and decay, then they release gases like CO2 and methane; if they rot, then they produce acids and humus.

If decomposers are gone, then dead matter cannot break down; if matter doesn't break down, then nutrients stay locked away from new plants.

If fungi do not have chlorophyll, then they cannot use the sun; if they eat dead matter instead, then they are decomposers, not plants.

If a plant needs to maximize surface area, then it grows tiny extensions; if these are on the root, then they are called root hairs.

If animals and roots move through soil, then they leave physical gaps; if gaps are created, then atmospheric oxygen fills those spaces.

If many species perform different roles (decomposing, aerating, fixing nitrogen), then the soil system is balanced; if balanced, then it is healthier.

If organisms break down dead matter, then they recycle nutrients; if they recycle nutrients into soil, then they are classified as decomposers.

If earthworms move through soil, then they create physical spaces; if these spaces exist, then air and water flow improves, aiding development.

If organic matter decays completely, then it forms a dark substance; if this substance provides nutrients, then it is known as humus.

If roots grow into small rock cracks, then they exert outward pressure; if pressure increases, then the rock breaks into smaller soil particles.

If an entity is living, then it is a biological factor; if bacteria, fungi, worms, and roots are all living, then they all contribute biologically.

If plants need nitrogen but cannot take it from air, then they need a soil source; if bacteria transform nitrogen, then plants can finally absorb it.

If animals burrow, then they mix nutrients and subsoil; if mixing occurs, then soil quality improves; therefore, they help rather than hinder.

If an organism eats a decomposer, then it is one step up the food chain; if it is one step up, then it is a secondary consumer.