Statements I. Terrestrial ecosystems include forests, grasslands, and deserts.

Statements II. Aquatic ecosystems include ponds, lakes, wetlands, rivers, and estuaries.

Both statements I and II are true.

The correct answer is Option (3) -Both statements I and II are true.

Statement I: Forest, grassland, and desert are examples of terrestrial ecosystems. The statement is true. Forest, grassland, and desert are all examples of terrestrial ecosystems. Terrestrial ecosystems refer to ecosystems that are found on land, characterized by the presence of soil and vegetation. Forests are areas with dense tree cover, grasslands are dominated by grasses and other herbaceous plants, and deserts are arid regions with limited vegetation.

Statement II:  Pond, lake, wetland, river, and estuary are all examples of aquatic ecosystems. The statement is also true. Aquatic ecosystems refer to ecosystems that are found in water bodies such as freshwater or marine environments. Ponds, lakes, and rivers are bodies of freshwater, while wetlands are areas where the water table is close to or at the surface. Estuaries are transitional areas where freshwater and saltwater mix, such as the meeting point of a river and the ocean.

Therefore, both statements I and II are true.