1. Classification means the grouping of organisms on the basis of a) How they feed
b) The features they have in common
c) How they respire
d) How they can survive

b) common features.

Explanation: Classification is the way we decide on relationships between groups of organisms, and this is done in several levels in a hierarchy. For example, all plants form a group based on having chlorophyll and being photosynthetic (the plant kingdom), which other kingdoms like animals and fungi do not. Within plants there are divisions, like angiosperms - plants with flowers. The closest relationships are between species in the same genus, plants that have the same kind of flowers and seed, like the Flanders poppy and California poppy.

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