<u>Answer:</u>
Recent evidence suggest that feathers evolved from scales and suggest that 'feathers and pycnofibers' could be homologous.
<u>Explanation:</u>
- One of the major difficult issue related to bird evolution is the evolution of feathers.
- Feathers are considered as the most 'complex integumentary structures' which are found in vertebrates.
- Evolutionary developmental biology suggests that the 'planar scale structure' is been modified for developing into feathers by 'splitting' to form web like structures.
- Scales and Feathers consist of 'two distinct form of keratin' so it was thought that 'each type was exclusive skin structure' but recent study suggests that they are developmental expressions of same skin structures.
Commensalism is when one organism benefits off the other one without harming it. Examples are tree frogs that use plants for protection or jackals that have been expelled from packs trailing tigers and feeding on the remains of its kill. Barnacles on whales get shelter by attaching to a whales body
The right answer is metaphase II.
The process is performed in two nuclear and cytoplasmic divisions, called first and second meiotic division or simply meiosis I and meiosis II. Both include prophase, metaphase, anaphase, and telophase. First division prophase is long and consists of 5 stages: leptotene, zygotene, pachytene, diplotene, and diakinesis. It is at this point that genetic recombination takes place at the level of chiasmus.
During meiosis I, the members of each homologous pair of chromosomes are paired during prophase, forming bivalents. During this phase, a protein structure, called synaptonemal complex form, allows recombination between homologous chromosomes. Subsequently, a large condensation of the bivalent chromosomes occurs and go to the metaphase plate during the first metaphase, resulting in the migration of n chromosomes to each of the poles during the first anaphase. This reduction division is responsible for maintaining the number of chromosomes characteristic of each species.
In meiosis II, as in mitosis, the sister chromatids comprising each chromosome are separated and distributed between the nuclei of the daughter cells. Between these two successive steps, there is no DNA replication. The maturation of the daughter cells will result in the gametes.
It absorbs oxygen while at the same time releases carbon dioxide across its surface
Answer:
it is w
Explanation:
i have done a similar question
