Plants & humans both life forms are very close to its relationship:

Chlorophyll molecules of green plants bear an intriguing similarity to Haemoglobin

Green plants act as respiratory apparatus or the lung of the earth.They produce oxygen and consume carbon dioxide, thus making condition favourable for the existence of mankind and all other forms of life. The similarity of plants and organs, the doctrine of signature is one of the first and most significant works of our time show how closely connected the liberal arts are to the clinical medicine. 

Some examples,

1. Carrot

A sliced carrot looks like the human eye, the pupils, iris and radiating lines just like the human eye. We all know about carrot's use for the eye.

 2. Tomato

The Tomato has four chambers and is red, the heart is red and it has four chambers. Recent searches portray tomatoes as useful vegetables for heart and blood.

3. Grapes

Grapes hang in a cluster that has a shape of a heart. Each grape looks like a blood cell and it is well-proved fact that they are good for the heart and it acts as a blood vitalizer.

4. Walnut

A walnut looks like a little brain. Even the wrinkles or folds on the nut are just like neocortex of the brain. It is essential for normal neurological functioning.

5. Kidney Beans

Kidney beans actually heal and help in maintaining the kidney function.

6. Avocados and Pears

Avocados look like a uterus and are related to the normal function of uterus and cervix of a female. When a woman eats one avocado a week, it balances hormones, sheds unwanted birth weight and prevents cervical cancer. Also, a striking similarity is that it takes exactly nine months to grow an avocado from blossom to a ripened fruit.

7. Figs

Figs are full of seeds and hang in twos when they grow. They increase the count and motility of male sperm and also improve the overall fertility of the male.

8. Sweet Potato

Sweet potatoes look like the pancreas and actually balance the glycemic index of diabetics.

9. Olives

Olives look like ovaries and assists the health and function of ovaries.

10. Citrus fruits

Grapefruits, Oranges and other citrus fruits look just like the mammary glands of the female and actually improve the health of breasts and it's lymphatic circulation.

11. Onion

Onion looks like body cells. Today's research shows that onion helps to clear waste material from all of the body cells. They even produce tears which wash the epithelial layer of the eyes.

12. Peanuts

Peanuts have a profound effect on testicles and sexual libido. Peanuts were banned by church often during the middle ages. Most of us unaware of the fact that arginine which is the main ingredient of Viagra, is extracted from peanuts.

13. Banana/Cucumber

Bananas, cucumbers and zucchini resemble the male sexual organ and also increase the strength.