The weight of an atom comes mostly from its 

______________ is exhibited by the roots of plants.

The _________ is the region of the atmosphere which absorbs harmful ultraviolet radiation.

_______________ are the animals which live on land but return to the water to breed.

Dolphins and whales are mammals that live in the sea. They feed their young on milk with mammary glands is the characteristic possessed only by mammals.

The liquid portion of the blood is the 

The building blocks from which all matter is composed are known as 

_________ is a vascular tissue that conducts water and minerals; phloem is a vascular tissue that conducts food.

________ is an environmental condition that has been blamed for the usual occurrence of fish kills.

A _____________ is any change that results in the production of one or more substances that differ in chemical properties and composition from the original substances.

Phenotype may be defined as visible expression of   _______.

Cell walls present in plant cells are made up of ___________.

Our diet must include three types of food: energy foods, body-building foods and maintenance foods. The energy foods are carbohydrates and ________.

Aspirin has been known to retard the blood-clotting process allowing us to use aspirin to reduce the possibility of stroke.

Elements are classified according to the number of protons in its __________.

The _____________ is an organism which is cold blooded with a dry scaly skin.

______________ are organisms responsible for the return of substances in the bodies of the dead plants and animals to the soil.

____________ promotes the development of secondary male sexual characteristics.

________________ is the iron-containing compound which give the red corpuscles its color.

Night blindness in children and adults is attributed to the deficiency in Vitamin ______ in the diet.