Why might a scientist repeat an investigation and not get the same results?

Why is stomach acid crucial for digestion?

If the blood flow to the brain ceases for 5 to 10 seconds, the muscles will start to twitch convulsively whithin how long?

What body system do the lungs convert carbon dioxide into oxygen?

Researchers have found a gene in yeast that codes for a myosin protein which is also coded by genes in humans. What does this similarity at the molecular level in yeast and humans indicate?

What microscope did Anton van leeuwenhoek use to observe single called organisms

Microbeads are tiny, smooth, plastic spheres found in common household products such as facial soap. These beads, measuring from 0.0004 to 1.24 mm, roughly the size of some fi sh eggs, are too small to be removed by water treatment systems.

Why should communities use sustainable practices to produce food

Most fungi are able to reproduce both asexually and sexually. Describe when asexual reproduction occurs and when sexual reproduction occurs.

Animals eat plant to get?

What relationship exists between trophic levels and a food chain