The choices can be found elsewhere and as follows:
1 a pesticide 2 an antibiotic 3 a vaccine 4 a toxin
The correct answer is option 3. A dead or weakened pathogen used to establish immunity would most likely be found in a vaccine. <span>A </span>vaccine<span> typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins.</span>
Solar energy is created by nuclear fusion that takes place in the sun. Fusion occurs when protons of hydrogen atoms violently collide in the sun's core and fuse to create a helium atom.
<span>The sun's
energy is the primary source of energy for all surface phenomena and life
on Earth. Combined with the material of the Earth (including the molecules
held close by the Earth's gravitational force called the atmosphere),
this energy provides for the immense diversity of life forms that are
found on the Earth. We will now look in detail at solar energy and its
interplay with the constituents of the Earth's atmosphere. </span>
