Answer:
A <u><em>receptor</em></u> is a protein that recognizes and responds to a signal.
Explanation:
A receptor is a protein molecule present on the cells on which the signalling molecules can bind and generate a physiological response. Some receptor molecules can also respond to Sun and light. Each type of cell has specific receptors molecules and hence can respond to specific signals. The receptor molecules hence tend to receive signals for a cell. Molecules such as hormones bind to the receptors.
Answer:
Alfred Lothar Wegener was a German polar researcher, geophysicist and meteorologist. During his lifetime he was primarily known for his achievements in meteorology and as a pioneer of polar research.
Answer:
Common examples include carbon, sulfur, oxygen, iron, copper, aluminium. Elements are represented by symbols. Compounds are substances made from atoms of different elements joined by chemical bonds. They can only be separated by a chemical reaction.
Explanation:
Substances can be categorised as either elements or compounds. Both of these are made up of atoms, the only difference is an element is made of one type of atom whereas compounds are made of two or more different types of atoms.