A chain of cells that attaches the embryo to the embryo sac.

Describe the various types of morphogenetic movements of epithelial cells during early changes in the embryonic form and formation of organ rudiments.

The cell of the pollen grain that divides to form sperms.

List one larval form for each of the following animal groups:

(i) Sponges

(ii) Molluscs

(iii) Cyclostomes

(iv) Hemichordates

(v) Coelentrata

With the help of a flow chart explain the processes involved in the initiation of flower primordial.

Define cleavage in fertilized egg and give its two main characteristic features. Describe the mechanism of cleavage in the fertilized egg.

The response of plants to touch.