Answer:
Brittle stars eat decaying plant matter (they are detrivores) and plankton, but can also kill small animals to eat as well.
Explanation:
They do this by pushing their stomach out through their mouth, like most starfish. Hope this helps.
Correct Answer is A. They were able to increase their productivity due to the popularity of tractors.
It is important because you need vitamins and minerals from them e.g. Scurvy no vitamin c
Answer:
<u>d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.
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Explanation:
Solutes are typically moved across the cell through either passive or active transport. The cells, surrounded by a bilipid layer or plasma membrane is amphiphlic- its polar, hydrophilic lipid heads face outwards, while their non-polar hydrophobic lipid tails face inwards towards each other.
While lipid-soluble molecules move across the layer easily, it is also difficult for charged and also large molecules to move across its surface, into the cell. Transmembrane channels, <u>embedded within the membrane</u>, help to maintain selective permeability as transport proteins, pores and gated channels. Simple diffusion happens as a method of passive transport in cells through plasma membranes.
The solutes travel through the plasma membrane in the process of diffusion from regions of high concentration to regions of low concentration; this occurs without the use of energy. <u>Molecules moving against their concentration require active transport mechanism to cross the membrane</u>.
Conifer tree is the tree that the leaf is slender like needle, it is evergreen tree more, material is general softer, some contain colophony , reason calls soft material again, its grows in elevation 100 ~ 1500 meters commonly, have economy and ornamental value.Conifers appeared 280 million years ago before any other trees.Conifers are believed to be the oldest trees on earth。
