Yajna is a very comprehensive term whose meaning is deep. You may, in a sense, say that the entire culture of Bharatavarsha is summed up in this single word, Yajna . Yajna is, therefore, the supreme effort of the soul to unite itself with God. Dana is the charitable disposition of the soul towards others. Charity does not mean only parting with a few paies or a few rupees or dollars or pounds.
Charity is an attitude of the mind.
It may be expressed in the form of physical action or it may not be so expressed. It includes charitable feelings, a charitable attitude, conduct and behaviour towards others. The capacity to appreciate the situation of others is charity. When you are in a position to enter into the feelings and the actual conditions and circumstances of other souls and other persons and feel as they feel and think as they think and act as they act, not with a sweating effort but with a spontaneous expression of your nature, that would be the essence of a charitable nature, - Dana. Tapas is personal discipline, bodily, verbal as well as mental.