Haemoglobin contains

Which of the following is a correct sequence for the appearance of compounds in a cell?

In the given figure,what is the bond angle represented by '$a$' (in $^\circ$)?

Choose the correct option ($T$-true,$F$-false).
$(I)$ Melting point of oil is lower.
$(II)$ All amino acids are acidic.
$(III)$ Lipid is water soluble.
$(IV)$ Enzyme shows its highest activity at a particular temperature.
$I - II - III - IV$

Nutritionally wild-type organisms,which do not require any additional growth supplements,are called .....

What is the main similarity between hormones and enzymes?