Name the animal tissue which acts as a heat insulator.

Give one reason for the following statements:
$(a)$ Blood is called a connective tissue.
$(b)$ Muscles are able to contract and relax to bring about movements.
$(c)$ Muscles of the heart are called involuntary muscles.

Give short answers:
$(i)$ What is the function of cambium?
$(ii)$ What is meant by lignin? Where is it present?
$(iii)$ What are the characteristics of cells of epidermis?

What are the two basic components of a connective tissue?

$(a)$ Why are complex tissues called so?
$(b)$ Why is connective tissue called so?
$(c)$ What is the function of the tissue present in the lining of kidney tubules?

$(a)$ Identify the given figures.
$(b)$ State in brief their structure.
$(c)$ Describe the role performed by the two.