English
The most commonly studied foreign language in France is English. About 40% of French people can speak English at an acceptable level or better.
French, followed by German and Spanish
No European languages can be considered "common" in Iran, but the most widely studied foreign language (after Arabic) is English, which is a European language.
Tu madre
English, followed by French.
Yes, English is the most common foreign language studied in school, followed by French.
Annual growth rings are commonly studied in trees.
Oxford
What subjects were commonly studied where and by whom?
Obstruction can be at various sites. You need to specify where the obstruction is
Usually in ancient times, foreigners, such as japanese, came to china and studied
The most studied plant is probably Arabidopsis thaliana, a small flowering plant commonly used as a model organism in plant biology research due to its small genome size, fast reproduction, and well-characterized genetics. Arabidopsis has been instrumental in advancing our understanding of plant biology, development, and response to various environmental stimuli.