Answer:
the third option, commensalism
Explanation:
Answer:
B. Directional selection
Explanation:
When natural selection starts to choose one phenotypes that is an extreme (as in, a really small neck or a really long neck), this is an example of <u>directional selection.</u> It makes sense for giraffes to have evolved this way, because the longer the neck, the more ably they can eat food from high branches. The more food they could get, the more chance of reproduction, the more "evolutionarily fit" they are.
Stabilizing selection is when national selection picks average phenotypes (like a medium-sized neck). Disruptive selection is when the extremes are both picked (like all the medium-sized neck giraffes die, and two different species start to emerge). Sexual selection is picking a mate based on traits. Clearly, those answers don't work here.
Muscles are required in breathing, talking, running, walking, and any body movement. Actin and myosins are protein filaments present in muscle cells that help to contract and relax or change the shape of muscles. Muscles are responsible for the movement or motion of organisms. Joints are the connection between two or more bones. Most joints are mobile.
Muscle strength is determined by several factors. Some of those are the physical shape, size, and innervation of the muscles.
Weak contraction
- Potassium accumulates in the sarcoplasm.
- Contracted lower sarcoplasm pH.
- Begin contraction with muscle already 50%.
- The circular arrangement of muscle fascicles.
Stronger contraction
- Increase in muscle belly circumference.
- A lesser proportion of motor neurons to muscle fibers.
- Increased recruitment.
- Increased stimulus frequency.
