Answer:a) a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates.
Explanation:
An ancestor - An earlier type of a species at any distant time — a progenitor.
A tetrapod is any vertebrate with four limbs. It includes any vertebrate (such as birds or snakes) that have evolved from early tetrapods — especially all members of the superclass Tetrapoda.
The presence of bones that support the appendages in Lobe – fin fish were found to be similar to the categorical skeletal supports found in the limbs of sample tetrapods. The sub class crossopterygii includes the Lobe – fin fish, which is seen as one of the recent common ancestor of living tetrapod today.
Producers
To understand food chains and food webs, we must start with where the energy begins. Sunlight is energy, and plants use this energy to turn water and carbon dioxide into plant food. This process is called “photosynthesis”. Plants also need minerals and nutrients. They get these from the soil when their roots take up water. While this might not sound like the kind of food you would want to eat, this plant food allows plants to grow, flower, and produceproduce things like acorns, potatoes, carrots, apples, pecans, and many other kinds of fruits.
Because plants make so much energy, they are called “producers”. Their ability to use sunlight to make food makes them a very important source of energy for other living things. Think about all the animals that eat plants. Wow, it's mind-boggling! Now, think about all the places that plants grow. From the oceans to the deserts to the mountaintops, plants can be found nearly everywhere basking in the sunlight and making their own food. And wherever plants grow, animals that depend upon them are sure to be found.
Glucagon is the hormone that helps in restoring the levels of blood glucose levels. It is produced by alpha cells of the pancreas. It stimulates the liver to break the glycogen, so that they may be utilized by the body, as a source of energy. It also stimulates glucose synthesis in the body.
