Q.Conservation of biodiversity within their natural habitat is

In-situ conservation protects species within their natural habitat; National Parks, sanctuaries and biosphere reserves are examples.

In-situ ('on site') conservation involves protecting species in their own natural habitat, allowing them to live and reproduce under natural conditions — examples include National Parks, Wildlife Sanctuaries and Biosphere Reserves. Ex-situ ('off site') conservation, by contrast, protects threatened species outside their natural habitat, as in zoological parks (zoos) and wildlife safari parks, where animals are maintained in captivity or artificially managed enclosures.

A Botanical Garden is an ex-situ (off-site) conservation method, unlike the other three in-situ options.

In-situ conservation protects species within their own natural habitat - examples include Sanctuaries, National Parks, and Biosphere Reserves.

Ex-situ conservation protects species outside their natural habitat, in controlled/artificial settings - examples include Botanical Gardens, zoological parks, seed banks, gene banks, and tissue-culture/cryopreservation facilities.

Since a Botanical Garden maintains plants away from their natural habitat, it is an ex-situ, not in-situ, conservation method.

Zoological parks fall under ex-situ conservation, since they keep animals away from their natural habitat, unlike the other three options.

In-situ conservation protects species within their own natural habitat and ecosystem -- Biosphere Reserves protect large representative ecosystems, Wildlife Sanctuaries protect specific species/habitats with some regulated human activity allowed, and National Parks strictly protect entire natural ecosystems with minimal human interference; all three keep organisms living in their natural surroundings. A Zoological Park, however, houses animals in an artificial, controlled environment away from their natural habitat -- the defining feature of ex-situ conservation, alongside botanical gardens, seed banks and captive breeding programmes.

Sundarlal Bahuguna is famously associated with the Chipko Movement — the answer is (c).

The Chipko Movement (Uttarakhand, 1970s) was a forest-conservation movement in which local people, especially women, embraced (hugged) trees to stop contractors from cutting them down ('Chipko' means 'to hug/stick'). Sundar Lal Bahuguna was one of its most prominent leaders (along with Chandi Prasad Bhatt).

• (a) Silent Valley Movement — associated with saving the Silent Valley forest in Kerala, not Bahuguna.

• (b) Bishnoi movement — the historical Khejarli sacrifice led by Amrita Devi Bishnoi.