A cell is the smallest unit that can independently carry out all necessary life processes. It serves as the basic building block for all living organisms.

Photosynthesis is the process by which plants convert sunlight into chemical energy. It uses chlorophyll to capture light and produce energy-rich molecules.

The nucleus contains the cell's genetic information in the form of DNA. It regulates cell function, growth, and reproduction.

Living organisms exhibit growth and the ability to reproduce. These characteristics are essential in distinguishing living organisms from non-living matter.

DNA (deoxyribonucleic acid) is the molecule that carries genetic instructions for the development and functioning of living organisms. It is essential for heredity and cellular regulation.

Mitochondria are known as the powerhouse of the cell because they generate ATP, the energy currency used by cells. This energy is essential for driving various cellular processes.

Mitosis is a cell division process that results in two genetically identical daughter cells. It is essential for the growth of multicellular organisms and the repair of damaged tissues.

Enzymes function as catalysts that lower the activation energy required for chemical reactions. This allows reactions to occur more efficiently without the enzyme being consumed.

DNA is structured as a double helix, a discovery that revolutionized our understanding of genetics. This configuration allows for the efficient replication and transcription of genetic information.

Natural selection is a cornerstone of evolutionary theory where favorable traits increase an organism's chances of survival. This process leads to the prevalence of beneficial adaptations in populations over time.

The circulatory system, comprising of the heart and blood vessels, distributes oxygen and essential nutrients throughout the body. It also facilitates the removal of waste products from cells.

Chlorophyll is the key pigment in plants that absorbs light energy during photosynthesis. Its presence gives plants their green color and is critical for converting light into chemical energy.

Eukaryotic cells are defined by having a nucleus that is separated from the cytoplasm by a membrane, unlike prokaryotic cells which lack such a compartment. This distinction is fundamental to cell complexity.

Meiosis is the specialized form of cell division that produces gametes with half the chromosome number of the parent cell. This reduction is crucial for maintaining genetic stability across generations.

Symbiosis refers to the long-term interactions between different species that live in close physical association. These interactions can be mutualistic, commensal, or parasitic, influencing ecosystem dynamics.

The rough endoplasmic reticulum (ER) is studded with ribosomes, which facilitate the synthesis of proteins. Its extensive network of membranes supports the processing and transport of proteins and lipids.

An ecosystem includes both the living (biotic) and non-living (abiotic) components and their complex interactions. This level of organization highlights the dynamics between organisms and their physical environment.

Mutations are a source of genetic variation, providing the raw material on which natural selection acts. While some mutations can be harmful, beneficial changes can enhance survival and reproductive success over time.

The human circulatory system is termed a closed system because blood is continuously circulated within vessels. This arrangement ensures efficient transport of nutrients, oxygen, and waste products while maintaining homeostasis.

Water is essential in cells for its unique solvent properties, which allow it to dissolve a wide range of substances. This facilitates numerous biochemical reactions and helps maintain the structure and integrity of cellular components.