Answer: b. Muscles
A metazoa is a division of animal kingdom that includes all animals expect protozoa and sponges. Metazoa division includes multicelluar animals, which exhibit highly differentiated cells. They have muscular and nerve system and well coordinated tissues and organs. Locomotion requires a coordination activity of muscular, skeletal and neural system. It is mainly achieved by contraction and relaxation of muscles that occurs due to specialized muscle proteins named as actin and myosin which receives signals from nerves.
Hence, locomotion in metazoa is due to contraction of muscles.
Answer:
The plants have the higher population density. This is because, when compared with that of the insects, the number of plant species per acre area is higher; 2800 compared to 683.3
Explanation:
The number of individual species per unit area of land is known as the population density. Population density describes how crowded or spaced out a given species is in a particular area. The higher the population density, the more crowded the species are and vice versa. The formula for calculating population density is given as:
Population density = Number of species/land area
Population density of the insects = 820/1.2 = 683.3 insects/acre
Population density of the plants = 560/0.2 = 2800 plants/acre
Therefore, the plants have the higher population density.
This is because, when compared with that of the insects, the number of plant species per acre area is higher.
All large radioactive atoms decay into smaller atoms by emitting alpha particles which consists of two protons and two neutrons. An alpha particle can also be thought of as the nucleus of a helium atom and as such they are sometimes referred to as He2+ . The positive charge is due to the lack of two electrons.
<span>contractile vacuole
Contractile vacuoles are organelles that are responsible for excretion function. They perform osmoregulation which manages wastes, water and other needed materials in the cell. They are found in some prokaryoric organisms like the algae, protists, amoeba and other unicellular organisms.
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