During Precambrian time, what did organisms not need

Which microscope do we use for objects as small as a nanometre?

A scientist observes some cells under a compound microscope and needs to determine if they are bacteria or yeast. Aside from size, what chemical compounds (not organelles!) would positively identify the cell as either a bacterium or a yeast?

Identify the structure where atp is produced.

What type of synovial joint allows for the most freedom of movement?

Are all flatworms hermaphrodites?

Drag each label to the correct location on the diagram. Each label can be used more than once. An incomplete diagram of the rock cycle is shown below. Use the labels to correctly complete the diagram

Deepest place in the seafloor is called the

Monohybrid cross is made between plants that

Which statement best describes an aerobic heterotroph

What disease disables the bodys immune system?