Chapter 7

Assertion: Cockroach is monoecious. Reason: Male and female sex organ is present in single organism.

Assertion: Earthworm possess moist body surface Reason: Earthworm respire through body surface

Assertion: Earthworm known as friend of farmers Reason: They make soil porous which helps in respiration and penetration of the developing plant roots.

Assertion: Development of earthworm is direct type. Reason: There is no larva stage in development.

Assertion: Frogs shows hibernation and aestivation Reason: This protect frog from extreme heat and cold respectively.

Assertion: Frogs are said to be cold blooded. Reason: Their body temperature varies with the temperature of environment.

Assertion: Frog shows sexual dimorphism Reason: Male frog can be distinguished from female by presence of vocal sacs

Assertion: Frog maintain ecological balance Reason: Frog serves as important link in flood web and food chain in the ecosystem.

Assertion: Frogs are beneficial to humans Reason: Frogs eat insect and protect our crops

Assertion: Cardiac muscle cell contract as a unit Reason: Communication junction (intercalated disc) present between the adjacent cells.