Q.Define growth as used in plant physiology, and state the one feature of plant growth (contrasted with most animals) that is called 'indeterminate' or 'open' growth.

[!TLDR]

Growth is an irreversible, permanent increase in size; plant growth is 'indeterminate' because meristems keep adding new growth throughout the plant's life.

[!ANSWER]

Growth = an irreversible, permanent increase in size of a cell, organ or the whole plant; indeterminate growth = growth that continues throughout the plant's life because of the presence of permanently active meristems, rather than stopping at some fixed adult size.

Growth, in plant physiology, is defined as an irreversible, permanent increase in size -- of a cell, an organ, or the whole plant -- typically measured by increase in fresh weight, dry weight, length, area, volume, or cell number. Unlike most animals, which largely stop growing once they reach adult size, plants exhibit indeterminate (or 'open') growth: because they retain localised regions of permanently dividing cells, the meristems, at their root and shoot tips (and, in many species, laterally as well), they continue producing new cells, and so new growth, throughout their entire life.

[!ANSWER]

Growth = an irreversible, permanent increase in size of a cell, organ or the whole plant; indeterminate growth = growth that continues throughout the plant's life because of the presence of permanently active meristems, rather than stopping at some fixed adult size.

State the formal definition of growth first, then explain indeterminate growth as a direct consequence of meristems persisting throughout the plant's life.

Describing growth only vaguely as 'plants getting bigger' without the key qualifier 'irreversible' -- a temporary, reversible size change (such as wilting and recovering) is not growth in this strict sense.