Muscle cells can stretch and contract. This is their specific cellular function. What type of molecule in muscle cells allow them to carry out this function? 1) sugars
2) RNA
3) fats
4) proteins

Which of the following is a good definition for the word adaptation? question 1 options: a trait that an organism survive and reproduce in its environment. a change in an organism's environment. the way in which animals obtain food. a temperature change that can cause the extinction of plants and animals.