bond order is the number of chemical bonds between a pair of atoms in a molecule. 
CO has 3 bonds between C and O, the bond order is 3 
N₂⁺ has bond order 2.5 
O₂ has bond order 2 
O₂^2- has bond order 1

Coat colour in cattle is an example of co-dominance. Thus the two dominant phenotypes express equally in the progenies. If the F1 individuals are self-bred then the phenotypic ration will be 1:2:1. The genotypic and phenotypic ratios are the same in case of a codominant monohybrid cross.

The ratio of A + T/G + C may vary from one species to another, but is constant for a given species, it is rarely equal to one and varies between 0.4 and 1.9.

Digestion of food in sponges completes in choanocytes. Choanocytes are also known as collar cells.

Porifera are generally marine but some are fresh water. And they are mostly asymmetric.

Taenia solium is attached to the intestinal mucosa by rostellum which is a knob like protruding part of the anterior end of tapeworms.

Scoliodon has minute placoid scales. Thus, they have tough skin.

The pyramid of number depicts number of organisms at each trophic level in a food chain. The pyramid of number is not upright in case of a forest ecosystem but is inverted in shape. Upright pyramid of number is observed in pond, lake and grassland ecosystems.

temperature and availability of soil water and chemical components of detritus play an important role in litter decomposition. The rate is high in tropical climate because of high temperature and high soil moisture while it is slow in temperate climates.

the standing crop is measured as the mass of living organism or the number in a unit area. 
It is defined as a certain mass of living material at a particular time at each trophic level. 
Standing state is defined as a certain mass of non living material at a particular time.

The gradual and fairly predictable change in species composition of a given area is ecological succession. During ecological succession, some species start to colonize an area and their populations become more numerous. Due to limitation of resources populations of other species decline and even disappear.