Why is it important to prevent thermometer from resting no the bottom of the test tube?

It's important to not touch the sides or the bottom of the test tube with the thermometer because touching it to the sides or bottom of the test tube fractures the glass and does not allow for correct temperature measurements.

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

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.