State whether the following statement is true or false:
Cotyledons represent a bit of pre-designed plant in the seed.

Characteristics of some organisms are given. Identify their group and give one example of each.
$(a)$ Single-celled,eukaryotic,and photosynthetic.
$(b)$ The body is divided into segments,may be unisexual or hermaphrodite.

Give one example of each:
$(a)$ Reptile which has a four-chambered heart.
$(b)$ Egg-laying mammal.
$(c)$ Parasitic Platyhelminthes.
$(d)$ Division among plants which has the simplest organisms.

Label $X$ and $Y$ in the given diagram of Hydra.

Give the differences between bony and cartilaginous fish.

Name two egg-laying mammals.