Grass → Rabbit → Snake → Hawk
A) In the above food chain grass is the primary producer. Rabbit is the primary consumer, snake is the secondary consumer and hawk is the tertiary consumer.
B) The arrows indicate the flow of energy from one organism to another. So these are always pointed from the food to the feeder.
C)
1. Plant → insect → frog → bird
2. Plant → insect → frog → snake
3. Aquatic plants → insects → fish → crane
4. Plant → mice → snake → vulture
5. Plant → aphids → spiders → birds