TOEFL Writing Task 1 [Integrated Task] – Practice Test #018

In recent years, many frog species around the world have declined in numbers or even gone extinct due to changes in their environment. These population declines and extinctions have serious consequences for the ecosystems in which frogs live; for example, frogs help play a role in protecting humans by eating disease-carrying insects. Several methods have been proposed to solve the problem of declining frog populations.

Frogs are being harmed by pesticides, which are chemicals used to prevent insects from damaging farm crops. Pesticides often spread from farmland into neighboring frog habitats. Once pesticides enter a frog’s body, they attack the nervous system, leading to severe breathing problems. If laws prohibited farmers from using harmful pesticides near sensitive frog populations, it would significantly reduce the harm pesticides cause to frogs.

A second major factor in frog population decline is a fungus that has spread around the world with deadly effect. The fungus causes thickening of the skin, and since frogs use their skin to absorb water, infected frogs die of dehydration. Researchers have discovered several ways to treat or prevent infection, including antifungal medication and treatments that kill the fungus with heat. If applied on a large scale, these treatments would protect sensitive frog populations from infection.

Frog populations are in decline because their natural habitats are threatened. Since most frog species lay their eggs in water, they depend on wetland habitats. Many such habitats are threatened by human activities, including excessive water use or the draining of wetlands for development. If key water habitats such as lakes and marshes were better protected, many frog species would recover.