Answer:
The Z lines and H- zone shortens during the muscle contraction.
Explanation:
Sarcomere is the area between the two Z lines. The Z- lines are present in the centre of I - band and H - zone is present in the A - band. The actin filaments which are thin filaments present in I- band and contracts, slide over the myosin filament during contraction.
The I - band, H- zones are became shortens as they are thin than the A- band. It is anisotropic band having thick myosin filaments. They are not flexible and remain in its constant shape during the muscle contraction.
After the muscle contraction, the A- band and the H- zone comes to their original shape. In other words, the sarcomere shortens and comes back during muscle contraction, and relaxation.
Answer:
The correct option is: <em>a deficiency of dopamine in the substantia nigra.</em>
Explanation:
The substantia nigra is the principal site involved in the physiopathology of Parkinson´s disease.
Cells from this area degenerate and die progressively causing important degeneration in the central nervous system. The cells that die -with no known reason- are those that produce dopamine and proportionate dopaminergic innervation to the encephalon. In fact, almost all the symptoms exhibited by patients with the disease can be explained by the lack of dopamine in the substantia nigra.
This area uses the neurotransmitter to communicate neurons from the base ganglia. Ganglia are responsible of modulating and modifying movements.
The nigrostriatal system participates in planning and automatic execution of learned movements. When the ganglia activity decreases, so it does the amount and velocity of movements, something typical of the disease.
SI units are a modern form of the metric system.
Answer:
<h3><u>Required Answer</u><u>:</u><u>-</u></h3>
The intensification of agriculture has caused dramatic declines in farmland biodiversity (Carvalheiro et al., 2013; Senapathi et al., 2015). Since the 1990s, agricultural policies have been developed in Europe to mitigate this loss through agri-environmental schemes (AES). One AES is “sown wildflower strips”, the aim of which is to create new ecological infrastructures by sowing attractive wild flowers on arable land (a few % of the cultivated area). These ecological infrastructures fall within our definition of MIMS since they represent a massive introduction of managed species in the landscape.
Answer:
As the population increases, the food supply, or the supply of another necessary resource, may decrease
Explanation:
