In mammals,Haversian canals are connected with each other by transverse canals,which are called:

Read the following statements about cockroach :
$(a)$ In male cockroach a characteristic mushroom shaped gland is present in the $6^{th}-7^{th}$ abdominal segments which functions as an accessory reproductive gland.
$(b)$ Cockroach is uricotelic.
$(c)$ The fat body and uricose gland help in excretion.
$(d)$ Blood from sinuses enter heart through ostia and is pumped anteriorly to sinuses again.
Which of the above statements are correct?

From which germ layer do the glands of vertebrates originate?

What is the correct order of excretory organs in Cockroach, Earthworm, and Rabbit, respectively?

The larva of a housefly lacks which of the following?

How many of the given statements are true?
$A.$ The dry surface of the skin and the moist surface of the buccal cavity are lined by compound epithelium.
$B.$ Cuboidal epithelium facilitates diffusion across the epithelium.
$C.$ Intercalated discs are the cell junctions between the cardiac muscle cells.
$D.$ Skeletal muscle fibers can be located in the biceps muscle.
$E.$ In a bone,osteocytes are located in lacunae.