Where is the options ???!!!
The statement, <em>“Bacteria set the stage for other life forms to evolve on earth” </em>was made probably because Earth was populated exclusively by single-celled organisms (Archaea and Bacteria) at the time that it was oxygenated, and only one of these can perform photosynthesis that separates a water molecule and results in oxygen gas, which is called Cyanobacteria, which has a blue-green color that comes from chlorophyll. Today, Cyanobacteria can practically be found everywhere on Earth, possibly in the soil right outside your door, and still play a vital role in producing the oxygen that we breathe. Another reason could be, billions of years ago, single-celled creatures had the planet to themselves. Then, they established different ways for cells to share and communicate resources. These intricate and complex multicellular creatures were the very first animals, and they were totally a major success. Consequently, animal life evolved about 540 million years ago.
A cell wall is a structural layer that surrounds some types of cells, situated outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides cells with both structural support and protection, and also acts as a filtering mechanism. Cell walls are present in plants, fungi and prokaryotic cells, where a major function is to act as pressure vessels, preventing over-expansion when water enters the cells. Cell walls are absent from mycoplasmas.
Homozygous tall pea plant has allele (TT)
Heterozygous tall pea plant has allel (Tt)
If we cross the two tea plants the genotypes produced are
TT x Tt
TT, Tt, TT, Tt
