Answer:
A. the digestive, muscular, and respiratory
Explanation:
Muscle weakness affects the muscular system (muscles are in the muscular system) , stomach pain affects the digestive system (stomach is a part of the digestive system), and coughing affects the respiratory system (coughing hinders the ability to breathe properly).
Exoskeleton
Exoskeleton is a evolutionary innovation. This is operated by muscles attached to it and acts as an armor. Other than support this is an adaptive mechanism to provide protection against predators. In vertebrates, it is considered as the dermal bone that developed via membranous ossification. Fishes retained their exoskeleton in the form of their scales. However, in some organisms terrestrial evolution allows the loss of exoskeleton and formed a more mobile endoskeleton,
Answer:
No
Explanation:
The Sun is a star there are lots of stars,but the Sun is the closest one to Earth.It made from gases and it always burning
Planets are:Mercury, Venus, Earth, Mars, Jupiter, Saturn, and Uranus
