All muscle cells share several properties: contractility, excitability, extensibility, and elasticity: Contractility is the ability of muscle cells to forcefully shorten. There are three types of muscle, skeletal or striated, cardiac, and smooth. Muscle action can be classified as being either voluntary or involuntary. Cardiac and smooth muscles contract without conscious thought and are termed involuntary, whereas the skeletal muscles contract upon command.

An axil is the angle between the upper side of a leaf and the stem from which it grows.

The location of the axil helps you to locate the bud because in flowering plants buds develop in the axils of leaves. These types of buds are known as axillary buds.

Energy is the ability to work. You need energy to force an object to move. You need energy to make matter change. The blowing wind, the warm Sun and a falling leaf are all examples of energy in use. Energy makes motion and change possible.

Wind power is energy, such as electricity, that is generated directly from the wind. It is considered a renewable energy source because there is always wind on the Earth and we aren't "using up" the wind when we make energy from it. Wind power also does not cause pollution.

Seeds wait to germinate until three needs are met: water, correct temperature, and a good location (such as in soil).

Different kinds of animals have different kinds of body coverings like:

1. Fishes - scales
2. turtle - shells
3. bear - fur
4. birds - feathers
5. humans - skins

Vegetative propagation is an asexual method of plant reproduction that occurs in its leaves, roots and stem. This can occur through fragmentation and regeneration of specific vegetative parts of plants.

Light is electromagnetic radiation that shows properties of both waves and particles. Light is a type of energy that makes it possible for us to see the world around us. We need light to see. Light comes from different sources called light sources; our main natural light source is the sun. Other sources include fire, stars and man-made light sources such as light-bulbs and torches. Light exists in tiny energy packets called photons. Each wave has a wavelength or frequency. ... In physics, the term light sometimes refers to electromagnetic radiation of any wavelength, whether visible or not.

1)- plants absorb carbon dioxide and provide oxygen . it is said that an average sized tree can absorb like 22 kg of co2 per year
2)- plants beings the herbivores support and provides food to other level of food web
3)- they can fix nitrogen in the soil. some plant root nodules can fix nitrogen
 eg:- rhizobium , azetobacter
4)- they can provide us shelter . Under a tree , there are thousands of insects and birds survive
5)- plants avoid soil erosion . Their roots can hold up the soils together
6)- the leaves of plants avoid and reduces the pressure of falling rain on the soil
7)- it is said that trees can reduce sound pollution

The primary function of photosynthesis is to convert the energy from the sun into chemical energy for food. With the exception of certain plants utilizing chemosynthesis, all plants and animals in Earth's ecosystem are ultimately dependent on the sugars and carbohydrates produced by plants through photosynthesis. Photosynthesis is the process by which plants and other things make food. It is an endothermic (takes in heat) chemical process that uses sunlight to turn carbon dioxide into sugars that the cell can use as energy. As well as plants, many kinds of algae, protists and bacteria use it to get food.

Chlorophyll is mainly present in the thylakoids of the chloroplast. It helps to absorb light and transfer that light energy by resonance energy transfer to a specific chlorophyll pair in the reaction center of the photosystems. This sunlight absorbed helps in the process of photosynthesis. 

Adaptation is the evolutionary process where an organism becomes better suited to its habitat. This process takes place over many generations. It is one of the basic phenomena of biology. When people speak about adaptation, they often mean a 'feature' (a trait) which helps an animal or plant survive. An example of a structural adaptation is the way some plants have adapted to life in the desert. Deserts are dry, hot places. Plants called succulents have adapted to this climate by storing water in their thick stems and leaves. Animal migration is an example of a behavioral adaptation.

Soil erosion is the natural process in which the topsoil of a field is carried away by physical sources such as wind and water.

Fungi are a group of living organisms which are classified in their own kingdom. This means they are not animals, plants, or bacteria. Unlike bacteria, which have simple prokaryotic cells, fungi have complex eukaryotic cells like animals and plants.

Digestion – Dissolving of solid food is called digestion. During digestion, the food containing large insoluble substances is broken down into small, water soluble substances. Digestion involves both physical and chemical methods for digesting the large substances present in food. The human digestive system consists of the alimentary canal and its associated glands. Food is taken into the body through the mouth.

Pangolins are uniquely covered in tough, overlapping scales. These mammals eat ants and termites using an extraordinarily long, sticky tongue, and are able to quickly roll themselves up into a tight ball when they feel threatened. Eight different pangolin species can be found across Asia and Africa.

Insects breathe with a network of tiny tubes called tracheae. Air enters the tubes through a row of holes along an insect's abdomen. The air then diffuses down the blind-ended tracheae. Since the biggest bugs have the longest tracheae, they should need the most oxygen to be able to breathe. Insects do not breathe through their mouths as we do. The do not have lungs and their blood, which is a watery, yellowish liquid, does not carry oxygen and carbon dioxide around their bodies. Insects have a system of tubes, called tracheae, instead of lungs. These tracheae penetrate right through the insect's body.

Jelly is usually made of gelatin, which is a protein. And protein, as we all know is a solid at room temperature. The gelatin is a sol (liquid) when hot, and a gel (solid) when cooled. 

Seeds dispersed by water are contained in light and buoyant fruit, giving them the ability to float. Coconuts are well known for their ability to float on water to reach land where they can germinate. Similarly, willow and silver birches produce lightweight fruit that can float on water. Plants which grow beside water often rely on water to transport their seeds for them. They may produce light seeds which float, or there may be fluff that helps buoyancy. ... They can colonise such isolated places because they both have very small, light seeds, which can be carried by the wind or by water.

Eye color was traditionally described as a single gene trait, with brown eyes being dominant over blue eyes. Today, scientists have discovered that at least eight genes influence the final color of eyes. The genes control the amount of melanin inside specialized cells of the iris. It was originally thought that eye color was a simple Mendelian trait, meaning it was determined by a single gene, with brown being dominant and blue recessive. It is now clear that eye color is a polygenic trait, meaning it is determined by multiple genes. Hence, colour of eyes is an inherited trait.