Biology 30 Genetics question

Which of the following descriptions of proteins are true? i. proteins can have different sequences of amino acids. ii. proteins can have different shapes. iii. proteins can have different numbers of amino acids. a. only i and ii are true. b. only ii and iii are true. c. only i and iii are true. d. i and ii and iii are all true. e. none are true statements

Groups of organisms with low biotic potential, such as gray whales, that produce at most one offspring every other year a) are r-selected b) are k-selected c) are not subject to density-dependent limiting factors d) show the initial stages of the extinction process e) have escaped from the processes of natural selection and adaptation

Which element provides strength to the exoskeleton of clams and oysters