Question

write two characters of phyllum mollusca​

Answer 1

Explanation:

1. They are bilaterally symmetrical.

2. Body is covered by a mantle and shell.

Answer 2

Answer:

• They are bilaterally symmetrical.

• They are triploblastic, which three layers.

• They show organ system grade of organisation.

• The body is soft and unsegmented.

• Body is divisible into three regions – head, a visceral mass, and ventral foot.

• Body is covered by a mantle and shell.

• They can be found in different habitats, both aquatic and terrestrial.

• The body cavity is a haemocoel, through which blood circulates.

• The digestive system is well developed and complex. It has a radula, which is a rasping structure that has chitinous teeth. It is used in feeding.

• The nervous system is made up of paired ganglia, connectives, and nerves.

• The circulatory system is open, with heart and aorta.

• Respiration occurs through gills called ctenidia.

• The ventral muscular foot helps in locomotion.

• They have a pair of kidneys (metanephridia)

• Sexes are separate and reproduction is through sexual reproduction.

• Fertilisation can be internal or external.