Solids have a fixed shape and volume because their particles are closely packed in a regular pattern. Liquids and gases take the shape of their container, and plasma is a high-energy state not typically encountered in everyday conditions.

Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose. The other processes serve different functions and do not involve the production of food.

Gravity is the force that attracts objects toward the Earth's center, causing them to fall. The other forces have distinct roles and do not account for the natural pull experienced by objects.

Solar energy is renewable because it is continuously harnessed from the sun. Fossil fuels such as coal, natural gas, and oil are finite resources that can eventually be depleted.

Nitrogen makes up about 78% of the Earth's atmosphere, making it the most abundant gas. Although oxygen is crucial for life, it does not constitute the majority of the atmosphere.

Mitochondria are known as the powerhouse of the cell because they produce ATP, which provides energy for cellular activities. Other organelles perform different functions such as genetic control and protein synthesis.

Evaporation occurs when particles at the surface of a liquid gain enough energy to enter the gas phase. Condensation is the reverse process, while precipitation and sublimation refer to different phase changes.

An ecosystem is a complex network where living organisms interact with each other and with nonliving elements such as air, water, and soil. The other options do not capture the full dynamic interaction present in an ecosystem.

Chemical energy is stored within the bonds of molecules and is released during chemical reactions. Kinetic and thermal energy refer to energy in motion or heat, while potential energy typically describes energy due to position.

Cells are the smallest structural and functional units of living organisms. While atoms and molecules are components of cells, it is the cell that represents the basic unit of life.

A thermometer is specifically designed to measure temperature by expanding or contracting with heat. In contrast, a barometer measures air pressure, a hygrometer measures humidity, and an anemometer measures wind speed.

The nucleus serves as the control center of the cell by storing genetic material and regulating gene expression. Other organelles, like mitochondria and ribosomes, have different roles such as energy production and protein synthesis.

Deposition is the phase change in which a gas transforms directly into a solid without passing through the liquid phase. Sublimation is the reverse process, and condensation involves a gas changing into a liquid.

Electrons carry a negative charge and orbit the nucleus of an atom. Protons have a positive charge, and neutrons have no charge, while the nucleus itself is composed of protons and neutrons.

Nuclear fission is the process in which a heavy nucleus splits into smaller nuclei, releasing energy in the process. Nuclear fusion, on the other hand, involves the combining of small nuclei, and the other processes do not involve splitting a nucleus.

The law of conservation of mass states that mass remains constant in a closed system during a chemical reaction. This means that the total mass of the reactants is equal to the total mass of the products, regardless of changes in energy.

Nuclear fusion is the process where light atomic nuclei join together to form a heavier nucleus, releasing energy in the process. In contrast, nuclear fission splits a heavy nucleus into smaller parts, and fusion is not a chemical reaction nor does it depend on a catalyst in the same way.

Ice floats on water because its crystalline structure forms an open lattice, reducing its density compared to liquid water. This lower density is crucial for aquatic life, ensuring that ice remains on the surface during cold periods.

An atom's chemical behavior is primarily determined by the arrangement of electrons in its outer energy levels. This electron configuration dictates how atoms interact and bond with one another, whereas neutrons and overall atomic size play secondary roles.

Rutherford's gold foil experiment revealed that atoms have a small, dense nucleus by demonstrating unexpected deflections of alpha particles. The other experiments explored different phenomena and did not directly identify the nucleus.