Use the coarse-focus knob to raise the stage until part of the threads comes into focus. Keep raising the stage slowly until all three threads are out of focus again. Now switch to the high-power objective. The threads are at different depths of view. To see each thread’s color, adjust the fine-focus knob. Top thread color: Middle thread color: Bottom thread color:

label a cell membrane

label b cytoplasm

label c ribosomes

label d dna

the membrane forms the outside of the cell

cytoplasm is the liquid within

ribosomes are the components within that distribute rna

the dna is the genetic make-up

1. is geographic distribution

2 is increasing complexity

3 is transitional forms

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.