1) My trainers (is/are) under my bed. Can you help me to find (it/them)? 2) What colour (is/are) your her hair now? – I don't know. She changes (its/ their) colour very often. 3) There (is/are) no money in my bag and I need (it/them) so much.

Solution:

1. My trainers are under my bed. Can you help me to find them? (Trainers is plural, so we use 'are'. 'it/them' refers to trainers, which is plural, so we use 'them').
2. What colour is your hair now? – I don't know. She changes her colour very often. (Hair is a non-count noun, so we use 'is'. 'its/their' refers to her hair, which belongs to 'she', a single person, so we use 'her' not 'its' or 'their').
3. There is no money in my bag and I need it so much. (Money is a non-count noun, so we use 'is'. 'it/them' refers to money, which is a non-count noun, so we use 'it').

Answer: 1. are, them, 2. is, her, 3. is, it