Biology Test 19

In Ascheminthes, the body cavity is not lined by mesoderm; instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called pseudocoelom and the animals possessing them are called pseudocoelomates.

Rhinoceros horns only consist of keratin, similar to human hair and nails. Rhinoceros horns are used in traditional medicines of both Europe and Asia, and for dagger handles in Yemen and Oman.

Earthworms have blood and it is enclosed in a network of tubes much like the blood system of mammals. It is red because it contains the oxygen carrying pigment haemoglobin. Unlike mammals, where the haemoglobin is inside red blood cells, earthworm haemoglobin is just mixed in the liquid of the blood, commonly called haemolymph.

In Earthworm, respiratory pigment haemoglobin is present in blood plasma.

The chaetae are made of chitin, a nitrogenous polysaccharide, which is hardened and darkened by impregnation with insoluble proteins known as scleroproteins. 
Chaetae are involved in the locomotion of earthworm.

The cells of the body are organized into tissues. Tissues into organs and organs into organ system. Except sponges and coelenterates, all the animals of the kingdom-Animalia have organ-system level of organization.

The members of Rhodophyceae are commonly called red algae because of the predominance of the red pigment, r-phycoerythrin in their body.

The number of chromosomes of the second generation will be same because no reduction division takes place.

Heterospory meant for the production of two different sizes of spores i.e., microspore and megaspore. It is found in Selaginella. In Selaginella, there is a small membranous ligule found at the basal portion of the leaf.