Answer:
d.The wing-assisted incline running theory postulates that wings were initially used to maintain balance while climbing up slopes.
Explanation:
Two theories were given to explain the origin of avian flight. The top-down theory suggested that the birds' ancestors were tree dwelling species. They took help of wings to glide from tree to tree in order to avoid predator or catch prey. The bottom up theory suggested that the birds' ancestors were ground dwelling species. They took help of wings to maintain a balance and provide a lift for efficient running.
Wing-assisted incline running was a mixture of both the above theories and gave a balanced view point. According to it, birds' ancestors used wings to maintain a balance while running up inclined slopes. The wings helped them to save energy while scaling slopes and eventually a flight mechanism was also developed.
<span>Nicotinic acetylcholine receptors (nAChR), are <span>ligand-gated ion channels and they can be a Na+, K+ and Ca2+ ion channel. Since nifedipine is a Ca2+ channel blocker (Ca2+ channel antagonist), it might inhibit the response of acetylcholine (if its receptor is Ca channel).</span></span>
Answer:
True
Explanation:
Truly, the typical X shaped chromosomes is the result of DNA replication. When the DNA has replicated, it then condenses and coil into the X-shaped of the chromosome. This then implies that replicated chromosomes take the X-shaped structures seen under a microscope.
When this replication occurs, the chromosome is made of two structures that are identical. They are known as the sister chromatids. These chromatids are actually joined at the centromere.
The Law of Superposition.
The Law of Superposition states that each layer is younger than the one beneath it.
It is gotten from the atmosphere by respiration, burning of fossil fuel, decay, excretion and decomposition of organic matter, fossilization etc
