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1. - A device used to initiate and control a sustained nuclear chain reaction.
4. - A positively charged subatomic particle found in the nucleus of an atom.
8. - Relating to the Earth's atmosphere or atmospheric phenomena.
9. - The ability of a material to allow fluids or gases to pass through it.
10. - The branch of science that applies the principles of physics to biological systems.
14. - The study of the form and structure of organisms.
15. - The emission of light by a substance that has absorbed light or other electromagnetic radiation.

2. - A chemical element fundamental to all life, forming the basis of organic molecules.
3. - The regions of Earth near the equator, characterized by warm temperatures year-round.
5. - An instrument used to see objects that are too small to be seen by the naked eye.
6. - The interaction of multiple elements to produce a combined effect greater than the sum of their individual effects.
7. - The measurement of electromagnetic radiation, including light.
11. - The time of year when the Sun reaches its highest or lowest point in the sky at noon, marking the beginning of summer or winter.
12. - A flow pattern in which the fluid spins around a central axis.
13. - A vast cloud of gas and dust in space, often the birthplace of stars