What was Anton van Leeuwenhoek’s contribution in the development of cell theory? A. He built the first compound microscope. B. He was the first to observe live cells in a sample of pond water. C. He concluded that cells exist in liquids. D. He stated that all living things are made of cells.

B. He was the first to observe live cells in a sample of pond water.

Explanation:

He was a self taught man that created the first microscopes which allowed him and others to see tiny organisms.

The other answers are not correct as Hans made the first microscope, cells existing in liquids were not a critical part of micro biology, and it was Schlieden and Schwann who created the cell theory that stated that all living things were made of cells.

the alkaline earth metals (beryllium (be), magnesium (mg), calcium (ca), strontium (sr), barium (ba), and radium (ra)) are a group of chemical elements in the s-block of the periodic table with very similar properties: shiny. silvery-white. hopefully this ? i didn't fully understand the question