Tubulysin D Is a Peptide-Based Marine Natural Product with Biological

Tubulysin D is a peptide-based marine natural product with biological activity.Identify the following structural features of tubulysin D.
(a) Place a box around any sp³ nitrogen.
(b) Star (*)any oxygen atom that has two oxygen lone pairs in sp²-hybridized orbitals.
(c) Place a number symbol (#)on any oxygen atom that is sp² hybridized as a consequence of having a lone pair in a 2p orbital.
(d) Use an arrow to point to any N atom that has trigonal planar geometry.