Bhakti, hatha and kriya are all varieties of what?

Yoga is a group of physical, mental, and spiritual practices or disciplines which originated in ancient India. There is a broad variety of yoga schools, practices, and goals in Hinduism, Buddhism, and Jainism. Among the most well-known types of yoga are Hatha yoga and Rāja yoga.

Bhakti yoga is a spiritual path or spiritual practice within Hinduism focused on loving devotion towards a personal god. It is one of the paths in the spiritual practices of Hindus. Hatha yoga is a branch of yoga that emphasizes physical exercises to master the body along with mind exercises to withdraw it from external objects. Kriya yoga has been described as directing one's life energy to revolve, upward and downward, around the six spinal centers (medullary, cervical, dorsal, lumbar, sacral, and coccygeal plexuses) which correspond to the twelve astral signs of the zodiac, the symbolic Cosmic Man.

In Sanskrit, the word yoga comes from the root yuj which means "to add", "to join", "to unite", or "to attach" in its most common senses. Yoga has been studied and is increasingly recommended to promote relaxation and reduce stress. It can even help alleviate some medical conditions such as premenstrual syndrome in Europe as well as in the United States.