different experimental conditions
different experimental models
different experimental systems
different experiments
different explanations
different exposures
different expression levels
different expression patterns
different expression profiles
different expressions
different extents
different extraction methods
different extracts
different facets
different factors

different families
different fashions
different features
different feeding habits
different feeding regimes
different females
different fields
different films
different filters
different findings
different firms
different fish
different fish species
different flow conditions
different flow rates
different flow regimes

different fluids
different fluorescent dyes
different food sources
different foods
different force fields
different forces
different forest types
different forms
different formulae
different formulations
different fractions
different fragments
different frames
different frameworks
different frequencies
different functional groups

different functional properties
different functional roles
different functionals
different functions
different fungi
different future
different gases
different gears
different gender
different gene products
different genera
different generations
different genes
different genetic backgrounds
different genetic lineages
different genotypes

different geographic areas
different geographic locations
different geographic regions
different geographical areas
different geographical locations
different geographical origins
different geographical regions
different geographical scales
different geometries
different gestational ages
different goals