John Dalton was the first scientist
<span>Not all elements have strong visible spectra in a flame</span>
A pure substance refers to an element or a compound that has no component of another compound or element. Pure substances are made of only one type of atom or molecule. Hydrogen gas and pure iron are examples of pure substances. Hydrogen consists of hydrogen atoms only while iron consists of only iron atoms. Mixing two pure substances results in a mixture. To separate the two, scientists use a method known as filtration. Mixtures can either be homogeneous or heterogeneous. The measure used to determine how pure a substance may be called purity. Besides hydrogen and iron, other pure substances include gold, diamonds, sugar, and baking soda.
Answer:
An ion channel, more specifically a calcium channel.
Explanation:
The electrical activity of the cells is regulated by ion channels. Calcium channels, also referred as the voltage-gated calcium channels constitute one group of a superfamily of ion channels. A change in voltage across the membrane or small molecules triggers calcium channels to open, allowing calcium to flow into the cell. Inside the cell, calcium acts as a second messenger, it binds to calcium sensitive proteins to induce different responses and support several functions such as muscle contraction, hormone and neurotransmitter secretion, gene regulation, activation of other ion channels, control of action potentials, cell survival, etc.
Answer:
Chemistry is the scientific study of the structure of substances, how they react when combined and how they behave under different situations.
