Answer:
Explanation:
A sperm and an egg each contain one set of 23 chromosomes. When the sperm fertilizes the egg, two copies of each chromosome are present (and therefore two copies of each gene), and so an embryo forms.
The correct answer is C-it may alter habitats or harm birds.
They cause climate change by trapping heat, and they also contribute to respiratory disease from smog and air pollution. Extreme weather, food supply disruptions, and increased wildfires are other effects of climate change caused by greenhouse gases.
Answer:
Explanation:
Muscle contraction is stimulated by the movement of an action potential moving along a nerve fiber to the muscles. This event follow some series of process before being stimulated.
1. The impulse arrives at the synapse and travels through the transverse tubules.
2. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released.
3. Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites.
4. Tropomyosin molecules bind to exposed active sites, linking actin and myosin.
5. Thin filaments are pulled over the thick filaments.
6. The muscle fiber shortens and contracts.
