Incorrect Pair: c) Sparrow, cow

Explanation:
- Mala paired animals with similar eating habits, but she made one incorrect pair.
- Let's analyze each option to identify the incorrect pair.

a) Bear, crow:
- Bears are omnivorous animals that have a varied diet including plants, berries, insects, fish, and small mammals.
- Crows are also omnivorous birds that feed on a wide range of food sources, including fruits, seeds, insects, small animals, and carrion.
- Both bears and crows have a similar eating habit of being omnivorous, so this pair is correct.

b) Lion, vulture:
- Lions are carnivorous animals that primarily feed on other animals, mainly large ungulates such as zebras, wildebeests, and buffalo.
- Vultures are scavenger birds that primarily feed on carrion, including the remains of dead animals.
- Both lions and vultures have a similar eating habit of being carnivorous or scavengers, so this pair is correct.

c) Sparrow, cow:
- Sparrows are small passerine birds that have a diet mainly consisting of seeds, grains, and insects.
- Cows, on the other hand, are herbivorous animals that primarily feed on grass and other plant materials.
- Sparrows and cows have different eating habits, with sparrows being omnivorous and cows being herbivorous. Therefore, this pair is incorrect.

d) Frog, snake:
- Frogs are amphibians that have a diet consisting mainly of insects, spiders, worms, and small invertebrates.
- Snakes are carnivorous reptiles that feed on a variety of prey, including small mammals, birds, amphibians, and other reptiles.
- Both frogs and snakes have a similar eating habit of being carnivorous, so this pair is correct.

Conclusion:
- Based on the analysis, the incorrect pair is c) Sparrow, cow, as sparrows are omnivorous and cows are herbivorous.