Sentence:  What data there are on <WSD>growth</WSD> indicate considerable variation in rate ; unfortunately , no one has kept complete records of one individual , whereas many have been made for a very short period of time . 
Meaning of the word marked with <WSD> tags:  (biology) the process of an individual organism growing organically; a purely biological unfolding of events involved in an organism changing gradually from a simple to a more complex level