what is their symbol?
The swastika, "Om" and the "Ashtamangala".
Jainism
Jain icons and arts incorporate symbols such as the swastika, "Om", and the "Ashtamangala". In Jainism, "Om" is a condensed reference to the initials "A-A-A-U-M" of the five parameshthis: ""Arihant", "Ashiri", "Acharya", "Upajjhaya", "Muni"", or the five lines of the "Ṇamōkāra" Mantra. The "Ashtamangala" is a set of eight auspicious symbols: in the Digambara tradition, these are Chatra, "Dhvaja", "Kalasha", Fly-whisk, Mirror, Chair, Hand fan and Vessel. In the Śvētāmbar tradition, they are Swastika, "Srivatsa", "Nandavarta", "Vardhmanaka" (food vessel), "Bhadrasana" (seat), "Kalasha" (pot), "Darpan" (mirror) and pair of fish.

The hand with a wheel on the palm symbolizes "ahimsā". 
where does most of the salt we eat come from Seawater. what is it composed of? Primarily of sodium chloride. what are its health benefits? The sodium present in salt helps nerves and muscles to function correctly, and it is one factor involved in the osmotic regulation of water content in body organs. is it used for religious purposes? Yes, it is used in various religious ceremonies of Hinduism, Jainism, Buddhism and Shintoism. what are the beliefs of the second religion? Jainism is transtheistic and forecasts that the universe evolves without violating the law of substance dualism, auto executed through the middle ground between the principles of parallelism and interactionism. can you mention some of their vows? The "Sallekhana" vow is a ritual to be observed at the end of life.
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Jainism [SEP] Symbols
The five colours of the Jain flag represent the "Pañca-Parameṣṭhi" and the five vows. The swastika's four arms symbolise the four realms in which rebirth occurs according to Jainism: humans, heavenly beings, hellish beings and non-humans. The three dots on the top represent the three jewels mentioned in ancient texts: correct faith, correct understanding and correct conduct, believed to lead to spiritual perfection. In 1974, on the 2500th anniversary of the nirvana of Mahāvīra, the Jain community chose a single combined image for Jainism. It depicts the three "lokas", heaven, the human world and hell. The semi-circular topmost portion symbolizes "Siddhashila", a zone beyond the three realms.