Scientists believe that dark matter may account for the unexplained motions of stars within galaxies. Computers play an important role in the search for dark matter information. They allow scientists to create models which predict galaxy behavior. Satellites are also being used to gather dark matterinformation.

Primary evidence for dark matter comes from calculations showing that many galaxies would fly apart, or that they would not have formed or would not move as they do, if they did not contain a large amount of unseen matter.

The first variety is about 4.5 percent of the universe and is made of the familiar baryons (i.e., protons, neutrons, and atomic nuclei), which also make up the luminous stars and galaxies. Most of this baryonic dark matter is expected to exist in the form of gas in and between the galaxies.

Pure energy is any field energy, like potential energy, any kinetic energy, like a fast moving particle, but no mass energy of stable or nearly stable massive particles which would require a process to turn into work.

The vacuum energy is a special case of zero-point energy that relates to the quantum vacuum. Using the upper limit of the cosmological constant, the vacuum energy of free space has been estimated to be 10−9 joules (10−2 ergs) per cubic meter.

So the full answer to the question of whether pure energy exists is: For all of the particles that exist, massive and massless, energy is only one property of them, and cannot exist independently.

The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers, such as plants and algae, use energy from sunlight to make food energy by combining carbon dioxide and water to form organic matter. This process begins the flow of energy through almost all food webs.

3.1 The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers such as plants, algae, and cyanobacteria use the energy from sunlight to make organic matter from carbon dioxide and water. This establishes the beginning of energy flow through almost all food webs.

1 All animals need food in order to live and grow. They obtain their food from plants or from other animals.

In order to survive, all living things need air, water, and food. Animals obtain their food from plants and other animals, which provides them with the energy they need to move and grow. An animal’s home (habitat) must provide these basic needs (air, water and food) along with shelter from bad weather and predators.

Concepts to Be Covered

• Animals need food, water, shelter, and space to survive.
• Herbivores can live only where plant food is available.
• Carnivores can live only where they can catch their food.
• Omnivores can live in many places because they eat both plants and animals.
• Habitat is the physical area where an animal lives.

Living things need need air, water, food and shelter to survive.

What four basic things do all animals need to survive? Animals need food, shelter from weather and predators, water, and a place to raise young.

We must have food, water, air, and shelter to survive. If any one of these basic needs is not met, then humans cannot survive.