Step 1: Know the two ways to conserve.
There are two big methods to save biodiversity. In-situ means saving species in their own natural home. Ex-situ means saving them away from home, in special protected places.
Step 2: Check statement I about sacred groves.
Sacred groves are patches of forest that local people protect for religious reasons. The plants and animals stay in their natural place, so this is in-situ conservation. Statement I is correct.
Step 3: Check statement II about national parks.
National parks are strictly protected by the government. No private ownership, grazing, or farming is allowed inside their boundaries. So statement II is wrong.
Step 4: Check statement III about wildlife sanctuaries.
Sanctuaries are a bit more relaxed than national parks. Some controlled activities, like limited and regulated eco-tourism, are allowed. So statement III is correct.
Step 5: Check statement IV about ex-situ methods.
Seed banks store seeds, and cryopreservation freezes cells or gametes at very low temperature. Both keep life safe away from the wild, so they are ex-situ methods. Statement IV is correct.
Step 6: Combine the correct ones.
Correct statements are I, III, and IV. The wrong one is II.
\[ \boxed{\text{I, III and IV are correct}} \]