Answer:
Muscles at the microscopic level are made of actin (thin filament) and myosin (thick filament) fibers in alternation and parallel to each other. During contraction, the fibres seem to slip against each other in opposite directions. Technically, the myosin head ‘walks’ on the actin – in an engage and release motion – with the help of ATP. Several actin and myosin fibers make up a myofibril. Each contractile unit in the myofibril is called a sarcomere – viewed as Z-discs at the microscopic level.
Answer:
both are good homes for mosquitoes
What day is it today. 2) What day of the week is tomorrow?<span>
</span>
Making a guess or hypothesis base on his knowledge or plants and seasons
Answer:
This study was focused on an Ecosystem level, as it involved soil properties and above-ground vegetation interacting with mentioned soil physic properties.
Explanation:
Ecological studies can be performed at different hierarchy levels:
- <u>Organism</u>: This is an individual physiologically independent from other individuals. At this level, it must be understood <em>how an organism survives</em> under certain changing <em>physic and chemistry conditions</em>, and how it <em>behaves</em> to reproduce, avoid predators, and find food.
- <u>Population</u>: Groups of individuals from the same species, with similar characteristics, capable of crossing, leaving offspring that live in the same habitat at the same time. At this level, it is interesting to know the <em>size of the population required to leave fertile offspring</em> that ensure the population will <em>survive over time</em>. It is also interesting to know <em>genetic variability </em>that allows <em>evolutive adaptation </em>to environmental changes.
- <u>Community</u>: Relationship or interaction between different species groups that live in the same habitat and at the same time. At this level, it is interesting to study <em>inter-specific interactions</em> that could cause <em>changes in the populations´ size</em>. These could be the cases of competition, predation, parasitism, mutualism, and etcetera.
- <u>Ecosystem</u>: Basic interaction unit between population and environment that turn in complex relations existing between living and non-living elements in a given area. In the example, interactions between recovering vegetation and soil properties, as non-living elements.
