that can be used when needed; available source of wealth; any necessity of life, such as water, nutrients, light, food, or space ??? ??? ??? retrieve to get; to retain possession of; to recall knowledge from memory ??? ??? ??? reunite to bring together again; to unite or join again, as after separation. ??? ??? ??? rigid unable to bend or be forced out of shape; not flexible; fixed and unmoving ??