- aerobic
- afterbirth
- algae
- alimentary canal
- amber
- ameba
- amino acid
- amoeba
- anaconda
- anaerobic
- androgynous
- antibody
- antigen
- antitoxin
- appendage
- arm
- armour
- asexual
- assimilation
- atrophy
- aviary
- bacteria
- bacteriology
- barnacle
- bile
- binocular vision
- bio-
- biochemistry
- biodegradable
- biodiversity
- biological
- biological clock
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- biomass
- biome
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- blind
- brain
- breathe
- breed
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- breeding
- bristle
- bulb
- capsule
- carbohydrate
- carbon dioxide
- carnivore
- cell
- cellular
- cellulose
- central nervous system
- cervical
- cholesterol
- chromosome
- circulation
- circulatory
- class
- clone
- cold-blooded
- conceive
- conch
- connective tissue
- copulate
- coral reef
- cornea
- coronary
- corpuscle
- cortex
- cortisone
- cowrie
- crab
- crawfish
- crayfish
- creature
- cross
- crossbreed
- culture
- decay
- decay
- decompose
- defecate
- denizen
- dextrose
- diaphragm
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- digestion
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- DNA
- dorsal
- dry rot
- duct
- dwarf
- dwarf
- ecological
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- egg
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- embryo
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- enzyme
- epidermis
- evolution
- evolutionary
- excrement
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- excrete
- excretion
- exhale
- extinction
- faeces
- family
- fang
- fat
- fatty acid
- fauna
- feces
- feed
- female
- female
- ferment
- ferment
- fertile
- fertility
- fertilize
- fission
- flank
- flatulence
- flesh
- fleshy
- flightless
- flora
- foetal
- foetus
- foliage
- fossil
- freak
- freshwater
- fructose
- gamete
- ganglion
- gene
- gene pool
- genera
- genetic
- genetic code
- genetic engineering
- genetic fingerprinting
- genetics
- genome
- genus
- gestation
- gland
- glandular
- glucose
- gluten
- gonad
- grass snake
- grow
- growth
- habitat
- haemoglobin
- hearing
- heart
- hemisphere
- herbivore
- hereditary
- heredity
- hermaphrodite
- hibernate
- histamine
- homing
- hormone
- host
- impregnate
- impulse
- incubate
- indigenous
- infected
- infertile
- infest
- ingest
- inhale
- inseminate
- insensate
- insulin
- integument
- intercourse
- interferon
- intestine
- invertebrate
- involuntary
- iris
- jaw
- jelly
- kidney
- krill
- lactate
- lactation
- lactic acid
- leech
- leg
- lesser
- lichen
- life
- life cycle
- life form
- ligament
- limb
- limpet
- lipid
- liver
- living fossil
- locomotion
- lymph
- lymph node
- male
- male
- mammal
- mandible
- mate
- mate
- membrane
- metabolism
- metabolize
- metamorphosis
- microbe
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- microorganism
- microscopic
- migrate
- migratory
- miscarriage
- molar
- morphology
- motor
- mould
- mouth
- mucous membrane
- mucus
- muscle
- muscular
- mutant
- mutate
- mutation
- natural history
- natural selection
- nature
- neck
- nectar
- nerve
- nervous
- nervous system
- neural
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- neurology
- node
- nose
- nostril
- nucleic acid
- nucleus
- nutrient
- nutriment
- oesophagus
- oestrogen
- olfactory
- optic
- organ
- organic
- organic chemistry
- organism
- orifice
- ossify
- osteo-
- outgrowth
- ovary
- overwinter
- oviduct
- oviparous
- ovulate
- ovum
- parasite
- pathogen
- pedigree
- pelvic
- pelvis
- penile
- penis
- pepsin
- period
- perspiration
- perspire
- photosynthesis
- phylum
- pigment
- pigmentation
- plankton
- plasma
- pollinate
- postnatal
- pregnancy
- pregnant
- premature
- prenatal
- product
- proliferation
- propagate
- protein
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- protozoan
- puberty
- pulmonary
- pulp
- pulsation
- putrefy
- putrid
- red blood cell
- regurgitate
- renal
- reproduce
- reproduction
- reproductive
- respiration
- respiratory
- respire
- retina
- root
- rot
- rot
- ruff
- sac
- saliva
- salivary gland
- salivate
- saltwater
- scale
- scallop
- scaly
- sebaceous
- secrete
- secretion
- semen
- sense organ
- sensory
- serum
- sex
- sex
- sexless
- sexual intercourse
- sheath
- shell
- sibling
- skeletal
- skeleton
- skin
- skull
- spasm
- spasmodic
- species
- specimen
- sperm
- spiderweb
- spinal cord
- spine
- spineless
- starch
- stem cell
- stimulate
- stimulus
- strain
- subject
- subspecies
- sucker
- sucrose
- sweat
- sweat
- sweat gland
- symbiosis
- systemic
- tail
- taxonomy
- teeth
- testosterone
- test-tube baby
- tissue
- trachea
- tube
- urethra
- uric
- urinate
- urine
- variety
- vector
- vein
- venom
- venomous
- ventricle
- vertebra
- vertebrate
- vivisection
- warm-blooded
- wean
- wildlife
- windpipe
- yolk
