it is the force with which a body is attracted toward Earth or another celestial body. This means that when you are in space, away from Earth, objects do not weight anything since they do not feel gravitational attraction to the Earth. Objects can have a large mass, but weigh nothing.
Answer:
The correct answer is A. active transport
Explanation:
There are two types of transport which helps in the transport of molecules across the cell membrane. These are active transport and passive transport. In passive transport, the molecules move across the membrane without any energy expenditure and down their concentration gradient.
In active transport, molecules move against their concentration gradient with the help of ATP so in active transport, molecules can be present in high concentration outside or inside the cell.
Sodium is an ion that moves by active transport in and out of the cell with the help of sodium-potassium pump so it's so the correct answer is A.
3 is parasitism, 2 is mutualism, and 1 is commensalism.
By looking at there chromosomes such as the x and y gametes
Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs, and have no body symmetry.
The shapes of their bodies are adapted for maximal efficiency of water
flow through the central cavity, where it deposits nutrients, and leaves
through a hole called the osculum. Many sponges have internal skeletons of spongin and/or spicules of calcium carbonate or silicon dioxide. All sponges are sessile
aquatic animals. Although there are freshwater species, the great
majority are marine (salt water) species, ranging from tidal zones to
depths exceeding 8,800 m (5.5 mi).
