Beause we cut down a lot of trees. Often, so many, that the health of a forest is irreparably damaged. A forest is not just a bunch of trees. It is a whole ecosystem, in which the trees anchor the growth of many other plant and animal species, hold the ground together to prevent erosion, and produce a lot of oxygen to support animal life. If you harvest too many of the trees, the local ecosystem stops being a forest and starts turning into something else
Answer and Explanation:
The steps of the sliding filament theory are:
Muscle activation: breakdown of energy (ATP) by myosin.
Before contraction begins, myosin is only associated with a molecule of energy (ATP), which myosin breaks down into its component molecules (ADP + P) causing myosin to change shape.
Muscle contraction: cross-bridge formation
The shape change allows myosin to bind an adjacent actin, creating a cross-bridge.
Recharging: power (pulling) stroke
The cross-bridge formation causes myosin to release ADP+P, change shape, and to pull (slide) actin closer to the center of the myosin molecule.
Relaxaction: cross-bridge detachment
The completion of the pulling stroke further changes the shape of myosin. This allows myosin and ATP to bind, which causes myosin to release actin, destroying the cross-bridge. The cycle is now ready to begin again.
The repeated cycling through these steps generates force (i.e., step 2: cross-bridge formation) and changes in muscle length (i.e., step 3: power stroke), which are necessary to muscle contraction.
Marshall Nirenberg and Heinrich Mattaeis contributed to out current understanding of the genetic code by discovering genetic codons. Their experiment deciphered the first of the 64 triplet codons in the genetic code by using nucleic acid homopolymer to translate specific amino acids. Their experiment cracked the first codon of the genetic code and showed that RNA controlled the production of certain types of proteins.<span />
Explanation:
- Visual and auditory stimuli both occur in the form of waves. Although the two stimuli are very different in terms of composition, wave forms share similar characteristics that are especially important to our visual and auditory perceptions. Waveforms of different types surround us at all times, however we only have receptors which are sensitive to specific types of wavelengths. In this section, we describe the physical properties of the waves as well as the perceptual experiences associated with them.
AMPLITUDE AND WAVELENGTH
- Two physical characteristics of a wave are amplitude and wavelength (figure below). The amplitude of a wave is the height of a wave as measured from the highest point on the wave (peak or crest) to the lowest point on the wave (trough). Wavelength refers to the length of a wave from one peak to the next.
The amplitude or height of a wave is measured from the peak to the trough. The wavelength is measured from peak to peak.
Wavelength is directly related to the frequency of a given wave form. Frequency refers to the number of waves that pass a given point in a given time period and is often expressed in terms of hertz (Hz), or cycles per second. Longer wavelengths will have lower frequencies, and shorter wavelengths will have higher frequencies
