1. who
2. what
3. which
4. which
5. who
6. who
2) b. Henry has got a hat which/that is red, green and blue.
c. Claire is a weiter who is very popular.
d. It is a salad which tastes delicious.
e. This is a picture which was painted by Joseph Turner.
f. He is a tescher who is very popular.
g. It is a machine which makes pasta.