Science: Characteristics of living things

It includes features from all cell types. ... A cell consists of three parts: the cell membrane, the nucleus, and, between the two, the cytoplasm. Within the cytoplasm lie intricate arrangements of fine fibers and hundreds or even thousands of miniscule but distinct structures called organelles.

All living things take their needs from their environment to stay healthy. Substances that a living thing can use as energy and for growth and repair of damaged tissues are called nutrients.

Living things exhibit some form of movement. Humans and animals can move around. Animals can move from one place to another by walking, flying, or swimming. But you rarely see a plant moving. Plants have parts like buds and leaves that track presence of sunlight.

Respiration is taking a breath or the act of breathing. An example of respiration is inhaling and exhaling air. An analogous process in anaerobic organisms involving some substance other than free oxygen.

Excretion is defined as the process of expelling waste matter, or the waste matter expelled by this process. When a person goes to the bathroom to urinate, this is an example of excretion. Urine is an example of excretion.

Growth is defined as a gradual development in maturity, age, size, weight or height. An example of growth is a wild teenaged girl becoming much calmer in her late twenties. An example of growth is a boy getting an inch taller between the ages of 14 and 15.

Sensitivity is the quality of being tender, easily irritated or sympathetic. An example of sensitivity is lights hurting someone's eyes. An example of sensitivity is a person who gets upset very easily. An example of sensitivity is how a friend treats another who's going through a tough time.

Reproduction means to reproduce. It is a biological process by which an organism reproduces an offspring who is biologically similar to the organism. Reproduction enables and ensures the continuity of species, generation after generation. It is the main feature of life on earth.