Which of these is a biotic factor?
a) topography
b) soil
c) air
d) bacteria

D) Bacteria is the correct answer.

Explanation:

The biotic factors include all the living components of the ecosystem.

They are classified into three groups:

producers are also termed as (autotrophs): examples are Cyanobacteria, plants.consumers are also known as ( heterotrophs): examples are Elephants, Zooplankton, Tuna decomposers  are also named as(detritivores) examples are Bacteria, Cockroaches, Termites..

thus bacteria is an example of a biotic factor.

Solids have a definite volume and shape because particles in a solid vibrate around fixed locations. Strong attractions between the particles in a solid restrict their motion, keeping them in place.

Explanation:

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