all seeds look the same. How do we know which seeds are healthy?

If we want to see that,which seed is healthy than we do a process  that we done when the seed going to wash and dry in sunlight.
if we want to see healthy see the first we put all seed in bucket with water and wee see a some seed that float above of water that damage seed and that seed inside water that healthy seed
 

Dear payal, To check which seed is healty follow the following steps 1)Take a beaker full of water 2) Put the seeds which your want to test Observation: The seed which flow on water are hollow and are useless which means they are not healthy. The seed which sink in water are healthy and can be used to produce better yield

STEP 1 : TAKE A WEIGH OF 100 GRAMS OF SEEDS 
STEP 2 : WASH AND DRY THEM IN SUN .
STEP 3 : TAKE A PLATE AND PUT THE SEED INTO IT .
STEP 4 : THROW THE SEEDS UP . 
CONCLUSION : THE SEED THAT GET FLOWN AWAY ARE NOT HEALTHY SEEDS . THUS , THE SEEDS THAT FALL DOWN ARE HEALTHY SEEDS

take some seeds in a beaker fill it with water  after some time see the seeds the seeds which float on water are not good and are hollow so throw them out

take a beaker with water. add seeds into it .stir it .the seeds which float are unhealthy seeds where as seeds which settle at bottom of beaker are healthy seeds

TAKE WATER IN A BEAKER THEN PUT ALL THE SEEDS IN IT , LEAVE IT FOR SOMETIME , AFTER SOMETIME U WILL SEE THAT ALL THE UNHEALTHY SEEDS FLOAT IN THE WATER (WHICH IS IN THE BEAKER) AND HEALTHY SEEDS SINK IN THE WATER.

Healthy seed get sink in water

All are correct

All are correct

Damaged seeds will sink

take a bowlful of water put a handful of seeds in it the seeds which will float will be damaged and hollow from inside 
and the seeds which will sink in water are healthy seeds..