Explanation:
Scientists didnt belive that there are cells untill robert hooke (1665). He observed the cells in a cork slice with the help of a PRIMITIVE microscope
Leeuwenhoek (1674), with the help of an improved microscope, discovered free living cells in pound water for the first time.
It was robert brown in (1831) who discovered the nucleus in the cell.
Purkinjie in 1839 coined the term 'protoplasm' for the fluid substance of the cell.
THE CELL THEORY, that all plants and animals are composed of cells and that the cell is the basic unit of life, was presented by two biologists, schleiden (1838) and schwann(1839). The cell theory was fuether expanded by virchow (1855) by suggesting that all cells aris form PRE-EXISTING cells. With the discovery of the electron microscope in 1940,it was possible to observe and understand the complex structure of the cell and its various organelles.
Well, thats the history of the discovery of cells.
Answer:
Gravitational equilibrium helps maintain the environment in the Sun's core that is conducive to nuclear fusion. The Sun's gravitational equilibrium balances the gravity pulling inward and the pressure pushing outward. It keeps the Sun's size, denseness, and hotness stable, thus making nuclear fusion possible.
The given passage depicts the chivalric value that Gawain is displaying in the excerpt is - loyalty to his king
He is loyal to the king and says he will stand by the king. This show his devotion and dedication towards the king. This proves his loyalty towards him.
So the correct answer is loyalty to his king.
It's B
Explanation:
Because the fossil record shows how organisms have evoluate from relatively simple organisms to more complex organisms
Answer:
Air pollution harms human health and the environment. In Europe, emissions of many air pollutants have decreased substantially over the past decades, resulting in improved air quality across the region. However, air pollutant concentrations are still too high, and air quality problems persist. A significant proportion of Europe’s population live in areas, especially cities, where exceedances of air quality standards occur: ozone, nitrogen dioxide and particulate matter (PM) pollution pose serious health risks. Several countries have exceeded one or more of their 2010 emission limits for four important air pollutants. Reducing air pollution therefore remains important.
Air pollution is a local, pan-European and hemispheric issue. Air pollutants released in one country may be transported in the atmosphere, contributing to or resulting in poor air quality elsewhere.
Particulate matter, nitrogen dioxide and ground-level ozone, are now generally recognised as the three pollutants that most significantly affect human health. Long-term and peak exposures to these pollutants range in severity of impact, from impairing the respiratory system to premature death. Around 90 % of city dwellers in Europe are exposed to pollutants at concentrations higher than the air quality levels deemed harmful to health. For example, fine particulate matter (PM2.5) in air has been estimated to reduce life expectancy in the EU by more than eight months. Benzo(a)pyrene is a carcinogenic pollutant of increasing concern, with concentrations being above the threshold set to protect human health in several urban areas, especially in central and eastern Europe.
"Air pollution is causing damage to human health and ecosystems. Large parts of the population do not live in a healthy environment, according to current standards. To get on to a sustainable path, Europe will have to be ambitious and go beyond current legislation."
Explanation:
