Choose "a" or "an" and say the phrase with animal illustrations.

Let me work through this step by step to determine the correct articles (a or an) for each animal.

The rule is:
- Use "an" before words that start with a vowel sound (a, e, i, o, u)
- Use "a" before words that start with a consonant sound

Let me check each animal:

1. Dog and Cat
- Dog starts with "d" (consonant) → "a dog"
- Cat starts with "c" (consonant) → "a cat"

2. Camel and Elephant
- Camel starts with "c" (consonant) → "a camel"
- Elephant starts with "e" (vowel) → "an elephant"

3. Octopus and Frog
- Octopus starts with "o" (vowel) → "an octopus"
- Frog starts with "f" (consonant) → "a frog"

4. Fox and Rabbit
- Fox starts with "f" (consonant) → "a fox"
- Rabbit starts with "r" (consonant) → "a rabbit"

5. Owl and Crocodile
- Owl starts with "o" (vowel) → "an owl"
- Crocodile starts with "c" (consonant) → "a crocodile"

6. Tiger and Mouse
- Tiger starts with "t" (consonant) → "a tiger"
- Mouse starts with "m" (consonant) → "a mouse"

Let me verify my answers:
1. a dog and a cat ✓
2. a camel and an elephant ✓
3. an octopus and a frog ✓
4. a fox and a rabbit ✓
5. an owl and a crocodile ✓
6. a tiger and a mouse ✓

Final Answer:
1. a dog and a cat
2. a camel and an elephant
3. an octopus and a frog
4. a fox and a rabbit
5. an owl and a crocodile
6. a tiger and a mouse