Scientists say that many of the world's plants are in danger of [drying / dying] out – of becoming extinct. Dr Paul Smith, from Botanic Gardens Conservation International, said [one / once] in five of the world's plants is in danger of [extinct / extinction] . The world's botanic gardens [contents / contain] about 100,000 species, including a [third / thirdly] of all the world's endangered plants. Botanic gardens help to protect around 40 per cent of endangered [specials / species] of plants. They contain many of the rarest plants. Dr Smith said: "This is the first [times / time] that we have carried out a global assessment to look at the [width / wide] range of plants grown, managed and [conserved / conversed] in botanic gardens. For the first time we know what we have and, perhaps more [importance / importantly] , what is missing from botanic gardens."
Researcher Dr Samuel Brockington said the world's botanic gardens were the best [hoping / hope] for saving the world's [most / must] endangered plants. He said: "Currently, an estimated one-fifth of plant [diverse / diversity] is under threat, yet there is no [technical / technique] reason why any plant species should [become / becoming] extinct." Dr Brockington warned that if we do not protect [engendered / endangered] plants, people could have trouble finding food and fuel in the future. He said: "If [they / we] do not conserve our plant diversity, humanity will struggle to [solution / solve] the global challenges of food and fuel [security / secure] …and climate change." Most of the plants are in danger because of humans cutting down forests for farming and cities, and because of [pests / pasts] and climate change.