What is the one-word substitution for "the study of the structure and behavior of the physical and natural world through observation and experiment"?

• Science:
English meaning: (knowledge from) the careful study of the structure and behaviour of the physical world, especially by watching, measuring, and doing experiments, and the development of theories to describe the results of these activities.
Bangla meaning: সুশৃঙ্খল, সুবিন্যস্ত, বিশেষত পর্যবেক্ষণজাত ও পরীক্ষা-নিরীক্ষার দ্বারা যাচাইকৃত জ্ঞান; বিজ্ঞান।

Options,
• Physics:
English meaning: the scientific study of matter and energy and the effect that they have on each other.
Bangla meaning: বস্তু এবং শক্তিসম্পর্কিত বিজ্ঞান; পদার্থবিদ্যা।

• Chemistry: 
English meaning: the scientific study of the basic characteristics of substances and the ways in which they react or combine
Bangla meaning: রসায়নবিদ্যা।

• Biology:
English meaning: the scientific study of the natural processes of living things.
Bangla meaning: জীববিদ্যা।

Source: Cambridge Dictionary.