The answer is the percent composition which is number 4. This is the percent by mass of each element existing in a compound. To compute for this, you need to find two things: the mass of just the element, and the molar mass of the entire compound. Afterwards, you take the molar mass of only the element and divide it by the molar mass of the entire compound, and multiply by 100%.
Answer:
STM = Scanning Tunneling Microscope
Explanation:
STM and its significance
<em>It is the microscope that can take </em><u><em>images of the particles at the atomic scale</em></u><em>.It opens the door to under the </em><u><em>nano-scale process .</em></u>
<u><em>In 1986 Heinrich Rohrer won the nobel prize for its discovery</em></u>
<u><em>It doesn't magnify images like other microscopes .</em></u>
<u><em>It uses the principle of quantum tunneling. </em></u>
Working :
<em>A fine needle like tip is scanned on the surface of electrically conducting sample. When voltage is applied , the electron jumps between the suface of the tip and sample . This flow of electron is detected by the detector. It can resolve the image upto 0.000000001 m or 1 nm (nanometer)</em>
Uses :
- The STM is used in molecular science called nanotechnology to study nano phenomenon
- Its prototype AFM are used to Study wide range of Nano-particles
- STM is used in atomic deposition of metals with required scientific pattern, which can be used as nanodevices themselves.
- It is used to study electron-friedel oscillation on the surface of metals.
- It is used to modify sample surface.
<h2>Answer : Option A) Arm and leg muscles and option D) Striated or skeletal muscle</h2><h3>Explanation : </h3>
Voluntary muscles are those muscles which are and can be consciously controlled.
These includes biceps, triceps which are the muscles that are present in arms.
The leg muscles are also voluntary muscles, with addition to this the striated or skeletal muscles are also classified as voluntary muscles.
It is seen that most of the skeletal muscles are attached to bones by bundles of collagen fibers known as tendons are controlled voluntarily.
Answer: the correct answer is D) None of the individual insects should have possessed genomes that made them resistant to DDT.
Explanation: the problem is that DDT has become ineffective because insects have become more resistant to DDT.