Caterpillars are a rich source of protein.

Source: https://www.postandcourier.com/columnists/gardening-column-tent-caterpillars/article_940d5c68-e911-11ed-a245-3bd563c35f43.html

It provides our traditional diet and is a rich source of the stories of our existence.

Source: https://www.ipsnews.net/2023/05/global-plastics-treaty-can-end-age-plastic/?utm_source=rss&utm_medium=rss&utm_campaign=global-plastics-treaty-can-end-age-plastic

Its carcass soon becomes a rich source of food and habitat for smaller creatures.

Source: https://bigislandnow.com/2023/02/07/native-hawaiian-group-concerned-angry-over-response-to-dead-beached-whale-on-kauai/

Leafy greens such as kale, spinach, broccoli and cauliflower are also a rich source so including a variety of these in the diet is important.

Source: https://www.huffingtonpost.co.uk/entry/diet-and-fertility-link-explained-by-dietitian_uk_6450ba82e4b03c1b88cf0427

Meanwhile, passionfruit is a rich source of antioxidants such as Vitamin A, C, and B2, and vital nutrients like copper and potassium.

Source: https://www.therakyatpost.com/living/2023/07/15/sunsilk-natural-honey-passionfruit-will-keep-luscious-locks-hydrated-and-refreshed-all-day/

On injections of fat, which scientists call 'adipose tissue', they say it can 'induce hair regrowth' and is a 'rich source of stem cells'.

Source: https://www.dailymail.co.uk/health/article-12804951/Stop-balding-process-injecting-body-fat.html?ns_mchannel=rss&ns_campaign=1490&ito=1490

Pennsylvania has a long history as a rich source of fossil fuels.

Source: https://grist.org/energy/awash-in-toxic-wastewater-from-fracking-for-natural-gas-pennsylvania-faces-a-disposal-reckoning/

The romance and perils of life at sea provided rich source material for authors, and tales like The Adventures of Roderick RandomThe Rime of the Ancient Mariner (1798) were met with a of popular interest.

Source: https://www.cbc.ca/news/canada/newfoundland-labrador/english-language-nautical-slang-1.7001204?cmp=rss