a)
Similarities: both taking part in extreme sports, both wearing adequate safety equipment.
Differences: In picture A, the man seems to be taking part in a competition while in picture B, the man appears to be canoeing for leisure or in training. Also, the man in picture A is wearing lightweight clothing, while the man in picture В is wearing thick clothing.
b)
A: In both pictures, groups of people are taking part in extreme sports.
B: Yes, it looks like the people in picture C are about to do some indoor climbing. I think they are probably doing this sport for fun and to develop physical strength.
A: They could also be beginners who are doing the sport as a hobby. Perhaps the woman in red is instructing them, while the others are listening.
B: Maybe, but for this activity the people only have a climbing wall, some ropes and a lightweight harness. On the other hand, the people in picture D are carrying a great deal of equipment. It looks like they are going scuba diving. What do you think?
A: Yes, it seems like it. I think they must have training in order to do this, so they are probably experienced divers. I’d say they take part in this sport because they like to explore the ocean floor.
B: Yes, but they are possibly on holiday and looking to see beautiful coral reefs, or perhaps they are interested in marine wildlife.