Biology

Inheritance is the transmission of genetic information from one generation to the next. Genetic information is carried by DNA in chromosomes.

What is a drug? A drug is a substance that modifies chemical reactions in the body. Drugs can change how cells, tissues, organs, or organ systems work. Some drugs are used as medicines to prevent or treat disease; other drugs may be harmful or addictive. The effect of a drug depends on the chemical reaction or process that it changes. A drug may: reduce symptoms; destroy or inhibit a pathogen; or change the activity of body cells. This guide focuses on antibiotics and antibiotic resistance. ...

Reproduction produces new organisms. Asexual reproduction uses one parent and produces genetically identical offspring. Sexual reproduction involves fusion of nuclei from two gametes, producing a genetically different offspring. Asexual and sexual reproduction Asexual reproduction Asexual reproduction needs one parent and no fusion of gamete nuclei. Offspring are genetically identical to the parent and to one another, except for mutations. Examples include: Binary fission in some single-celled organisms Budding in yeast Runners producing new plantlets in plants such as strawberries Bulbs, tubers, or stem cuttings producing new plants Advantages in a stable environment: ...

Covers biological coordination systems, contrasting quick electric signals (Nervous System) with sustained chemical messages (Hormones). Emphasis placed on mechanisms like negative feedback (glucose homeostasis) and comparison of coordination methods across animals and plants.

Excretion is the process by which organisms remove waste products and excess substances from the body. In humans, excretion maintains internal balance by removing metabolic byproducts and regulating fluid and ion levels. Two primary systems handle human excretion: the respiratory system and the urinary system.