Answer:

Plasmodesmata play roles in both cellular communication and in molecule translocation. Plant cells must work together as part of a multicellular organism (the plant); in other words, the individual cells must work to benefit the common good. Therefore, communication between cells is crucial for plant survival.
<u>Answer:</u>
- few nutrients
- high pressure
- low temperatures
<u>Explanation:</u>
1. Few nutrients: open-ocean zone is located way far from the land, which is the main source of the essential nutrients.
2. High pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.
3. Ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface.
4. Varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.
5. Low temperatures: the temperature of open-ocean zone ranges from a low of -2°C to an average of 17°C.
Majority of animals on earth are classified as invertebrates. They are the cold-blooded animal that do not have a backbone. They can be found on land or water. 98% are invertebrates while 2% are vertebrates.
Mammals are vertebrates and humans are the most common mammals on Earth. Radial symmetric does not possess left and right sides. An example is a jellyfish.
Answer - Option 4 - Invertebrate
South America has the largest grassland of Earth.<span><span><span /></span></span>