Oak

Scientific name: Quercus spp.
Habitat
This is found in the northern hemisphere and extends from cold latitude to America and Asia

Oak is basically a tree and its leaves are arranged spirally, its bark is used for medical purposes.
Use
This is helpful against diarrhea and curing dysentery and it can be applied externally to swollen tissues, wounds and bruises. As it is hard tree and its wood is used as furniture also.

It can be taken during pregnancy and breast feeding but it sometime can cause constipation but is quite safe for use by children and infants. 

Oats

Scientific name: Avena sativa, A. fatua
Habitat
It is considered as annual grass and can grow up to 4 feet height.
Use
It is helpful in fighting against illness and it provides rwuired fibre in our diet and its pastes helps in curing many disorders like acne.
Onion Scientific name: Allium sepa

Habitat
IT is a perennial herb and it requires dry location in a temperature ranging from 35 and 50 degrees. It is extensively found in India and other parts of the world. It can be grown from seeds or from sets, and these sets are produced by sowing seeds thickly in a year.

They are frequently used in college labs as their property includes large cells and it helps in proper visibility through low end optical microscope

Use
They are really rich in many properties like water and low calorie and hence help in various diseases.

It can be used for external purposes as an antiseptic and internally also it can relive from gas pains and can reduce hypertension and cholesterol, Apart from medicines it is extensively used in Indian coking as it is a part and parcel of every food and its inclusion adds wonders in its taste, They are rich in water level and energy and have low calories, they got a generous amount of B6,B! and folic acid.

It has got chemicals which helps us to fight against the free radicles produced in our body which can cause disease and cells destruction and further are associated with 60 and more disease. If they are consumed properly buy a person then it increases cholesterol by average of 30% it increase circulation low down the blood pressure and is helpful in blood clotting.

Orange

Scientific name: Citrus aurantium
Habitat
IT is basically found in a rich and sandy soil and prefers warm year and round temperatures and is found in plenty In India n subcontinent
Use
Its basic purpose is that it is used as fruits and its syrup and juice provides energy and is very light in nature and really helpful for many patients suffering from end number of diseases.. it relies from giddiness and vomiting

Oregano

Scientific name: Origanum vulgare
Habitat
It is a perennial and prefers drained and alkaline soil and needs full sun.
Use
It is a viable herb against colds, flu and fevers, It relives from menstrual discomforts and helpful in clearing bronchial.