Hydrogen bonds.
The nucleotides in a base pair are complementary which means their shape allows them to bond together with hydrogen bonds. The A-T pair forms two hydrogen bonds. The C-G pair forms three. The hydrogen bonding between complementary bases holds the two strands of DNA together
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.
There are three types of dominance. Incomplete, complete, and co-dominance. Complete dominance is when the dominant trait completely masks the recessive. incomplete dominance is when the dominant allele doesn’t completely mask the recessive allele, sometimes resulting in blending. Co-dominance occurs when both alleles are expressed at the same time.
