Answer:
The correct answer is because they have same number of protons but different number of neutrons.
Explanation:
Isotopes are atoms of the same element but differ only in the number of neutrons in the nucleus, i.e. they have same atomic number but different mass number.
Mass number is affected as they have different number of neutrons, thus effecting their physical properties.
The number of electrons and protons are same, i.e. their atomic number is same and thus their chemical properties are same as chemical properties are determined by the atom’s electronic configuration and that relates to number of protons.
Answer:
Freezing: Liquid turns into solid. Evaporation: Liquid turns into gas. Condensation: Gas turns into liquid. Sublimation: solid into gas. Deposition: Gas into solid.
Explanation:
It would be a solid because at -20 °C it has turned to ice
Answer:
See the answer below
Explanation:
There are several scientists that contributed to the understanding of the cell. Some of them and their contributions are as follows:
Anton van Leeuwenhoek: He invented the first primitive microscope and was able to view some unicellular microscopic cells such as protozoans and bacteria. He disproved the theory of spontaneous generation by his discoveries.
Robert Hooke (1665): He improved further on the microscope invented by Leeuwenhoek and was able to view compartment-like rooms when tissues of cork were sectioned. He tagged the compartment as 'cell'.
Schleiden (1804–1881): Using an improved microscope, he was able to extensively study plant tissues and borrowed the word coined by Hooke (cell) to describe the component of the plant tissues.
Theodor Schwann (1810–1882): He studied animal tissues and made a similar observation as Schleiden.
Through their various studies, Schleiden, Schwann, and another scientist, Rudolf Virchow later developed what is nowadays known as the cell theory
By studying seismic waves
Explanation:
Scientists discovered that the earth's outer core is liquid by simply studying seismic waves.
Seismic waves are elastic waves that have been used by geophysicists to study the earth's interior.
- Interior of the earth is inaccessible due to high pressure and temperature conditions therein.
- To study this part of the earth, an indirect method should be used.
- Seismic waves produced during an earthquake due to their permeating nature have been used to study the interior.
- Seismic P-waves can pass through any materials because they are longitudinal waves. They go through solids, liquids and gases.
- S-waves can only pass through solids and not fluids.
- On a seismograph, it was discovered that the S-waves were cut off in a part of the reading.
- The waves re-appeared after a distance.
- Since S-waves cannot pass through liquids, it has been hypothesized that the outer core is liquid.
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