1.Various kinds of plants grown at a place constitute a crop.

TRUE / FALSE AND HOW?? PLEASE EXPLAIN

2. Sowing of seeds at varying (different) depth and distance gives good yield.

TRUE / FALSE AND HOW?? PLEASE EXPLAIN

Dear student,
Please find below the answer:

1. False.
Plants of the same kind (not of various kinds) grown on a large scale for food, clothing, etc., are called crops. For example, several plants of maize grown in a large field form a crop of maize. Examples of food crops are cereals, fruits and vegetables. 

2. False. 
Seeds should be sown at appropriate depth (not varying depths) because if they are sown at shallow depth then it can be easily be affected by wind or animals and if they are sown at greater depth then there would be lack of air and water. Therefore it is absolutely necessary to sow plants at appropriate depths. 

It is important to sow seeds at an appropriate distance from each other so as to provide them with the right amount of water and sunlight when they grow up.

Hope this clears your doubt.
Regards.