The reasons are:
- the blood is very low on nutrition
- the leech is not feeding itself regularly
The leech slows it metabolism a lot, so it can survive on very low nutrition. The blood is very low on nutrition, and it is the leech's food source, so the evolution made it preserve energy.
The leach doesn't have the opportunity to feed itself on regular basis, so it takes maximum advantage of any opportunity and consumes as much blood as possible so that it can survive long term when it will not have food at disposal.
The main difference between a prokaryotic cell and a eukaryotic cell is that the prokaryotic cell have no true nucleus instead its genetic material is just suspended in its cytoplasm termed as nucleoid. The nucleus when viewed under the microscope is a membrane bound which is easily distingushable compared to the nucleoid.
Another distinguishing feature is that prokaryotic cells are usually smaller than eukaryotic cells.
Answer:
A) Golgi tendon organ.
Explanation:
A tendon organ or neurotendinous organ or Golgi tendon organ is a mechanoreceptor located at the insertion point of the skeletal muscle to the tendon that is at the myotendinous junction.
The Golgi tendon organ is composed of the collagenous muscle fibres which contain the receptors which sense the contraction of active stretch of the muscles and sends it to the brain. The brain sends the response and the muscle act by the inverse myotatic reflex.
Thus, Option-A is the correct answer.
They have a shell, which is attached to their body, unlike other creatures. <span />
Answer:
They each have vestigial structures.
Explanation:
Birds and humans have a common ancestor as they have homologous structures.
Vestigial structures are the organs that have some important functions in the past but now in present, they do not perform any function.
Both humans and birds have vestigial structures such as humans have an appendix and ear pinna and wings of flightless birds such as ostrich.
Hence, the correct answer is "They each have vestigial structures.".
