Answer:
Sonic Hedgehog.
Explanation:
Sonic hedgehog is a secreted protein that in humans is encoded by the SHH gene. It is the best studied ligand of the hedgehog signaling pathway, others being desert hedgehog (DHH) and Indian hedgehog (IHH). It plays a key role in the development of animals, from insects to mammals. In vertebrates, it is involved in organogenesis, including the growth of digits on limbs and the organization of the brain.
Sonic hedgehog has also been shown to act as an axonal guidance cue. It has been demonstrated that SHH attracts commissural axons at the ventral midline of the developing spinal cord. Specifically, SHH attracts retinal ganglion cell (RGC) axons at low concentrations and repels them at higher concentrations
The answer is A. a light wave
C and D both need water as a medium and sound needs air to vibrate in order to travel. light, on the other hand, does not need a medium
Human and apes have 5 fingers that are used for grasping objects, so they have the same function, but they also have a common ancestor and are closely related, that means that this is an example of homologous structures. In evolutionary biology, the term homologous structures means that there are organs and skeletal elements of animals and organisms, that by virtue of their similarity, suggest their connection to a common ancestor.
Answer:b. an mRNA transcript to which multiple ribosomes are attached
Explanation: polysome consist of mRNA complex and two or more ribosome coming together to translate mRNA into a polypetide or amino acid. It helps produce many polypeptide from a single mRNA.
Different ribosomes bind to the mRNA at different time elongating the polypeptide chain. We have the free( non-poly A ) and memberane bound (poly A) polysome.
