Cyclic photophosphorylation is performed by PS-I only. In this process, an electron expelled by the excited photo centre, ie, P₇₀₀ is returned to it after passing through a  series of electron carriers. 

PS- I is located on both the non- appressed part of grana thylakoids as well as stroma thylakoids, while PS-II is located in the appressed part of grana thylakoids only, stroma thylakoids lack PS-II.

In earthworm, the excretory system is made up of many segmentally arranged microscopic coiled tubes called nephridia. These are ectodermal in origin and analogous to the vertebrate kidney.
In Pheretima, following three types of nephridia are seen.

(i) Pharyngeal nephridia - Situated on either side of pharynx and oesophagus in 4, 5 and 6 segments.

(ii) Integumentary nephridia - Scattered in the body wall, seen from 7th segment onwards

(iii) Septal nephridia - Largest nephridia attached to both faces of each intersegment septum behind 15th segment

Tea plants are grown by stem cuttings. If we dip the lower cut end of a cutting in a dilute solution of auxins (IAA, IBA etc) , large number large number of roots are developed on the cut ends, due to which these cutting develop into successful plants.

Root nodules of leguminous plants harbour symbiotic bacteria, Rhizobium, which fixes atmospheric nitrogen and provides the plant with most or all of its nitrogen requirements. In return, they have access to a rich supply of carbohydrate. The fixation of atmospheric nitrogen (N₂) to ammonia (NH₃) occurs within the nodules, using the enzyme nitrogen cut this enzyme is very sensitive to oxygen and gets inhibited in oxygen rich environment. This problem is solved by leghaemoglobin, a pinkish-red, oxygen-binding, iron-containing protein present in root nodules. It functions as oxygen buffer, scavenges oxygen and provides the enzyme nitrogenase, a low oxygen environment in which nitrogen fixation can occur.

Nostoc is a blue-green algae capable of fixing nitrogen. 
Glomus is associated with endomycorrhiza.
Agaricus or mushroom is an edible fungus of class-Basidiomycetes.
Rhizobium is a symbiotic nitrogen -fixing bacterium found in the root nodules of leguminous plants.

Arteries are the blood vessels which carry blood away from the heart. In comparison to veins, arteries have a narrow lumen and more muscular thick walls to bear the pressure of pumping action of the heart.
Angina is constricting chest pain caused due to reduced blood supply to the heart wall.
Persons with blood group- AB are universal acceptor, while those with blood group -O are a universal donor. 

The normal haemoglobin count is about 15 gm/100 mL of blood in males, while for females the haemoglobin count is slightly less, ie, 13 gm/100 mL blood.

opuntia is a plant growing in dry and xeric habitats.In this, the stem, having several nodes and internodes is modified into flat, fleshy, thick green,  leaf-like structure called phylloclades. Phylloclade performs the function of photosynthesis like a leaf and also stores food leaves get modified into spines which help to reduce transpiration.

Cartilage is usually described as a vascular, as the blood vessels innervate only the outer fibrous sheath of cartilage, called perichondrium. The cornea is the transparent anterior portion of the outer coat of the vertebrate eye covering the iris and the pupil. It is avascular as it lacks lymphatic and blood vessels.

The parietal cells or oxyntic cells are large, rounded cells located upon the surface of gastric glands. These cells secrete HCl (which converts inactive pepsinogen into active pepsin) and Castle's Intrinsic Factor of CIF (which helps in the absorption of vitamin -B₁₂ or cyanocobalamine). If somehow, parietal cells become partially non-functional, the patient will suffer from achlorhydria (no HCl) or hypochlorhydria (less HCl).This will result in the non- activation of pepsinogen due to which proteins will not be adequately hydrolysed into proteoses and peptones. Lack of CIF will cause vitamin-B₁₂ deficiency, which will result in pernicious anaemia.