in this case the shrew occupies the level of both secondary and tertiary consumers.
as the shrew eats spider( a secondary consumer) so it is a tertiary consumer but it also eats snails( a primary consumer) so it is therefore a secondary consumer also.
so the shrew occupies both secondary and tertiary consumer trophic level.
abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems.