<span>The cells of plants
and animals are similar expect for a few different structures like the shape of
the cells and cell wall. They differ in cell shape since animal cells are rounded
and it has irregular shape while plant cells have fixed shape which is
rectangular. Another structure is a cell wall. Animal cells don’t have cell wall
while plant cells have. Plant cell wall is a structure surrounding the cell
that provides a number of functions such as strength to support the plant, Flexibility,
Water-proofing, Barrier to pests, Protection against environmental stress, signaling
and sensing. </span>
A, B, D, and E are all wrong. C is the right answer. C is a compound.
A, B, D and E are not unique. A pure substance is something with unique characteristics and if it can be broken down, the result is two or more pure substances. AKA only compounds and elements. This is an easy question so try to study.
Vitamin A deficiency is the leading cause of preventable blindness in children.
This mechanism allows killer T-cells to hunt down and destroy cells that are infected with germs or that have become cancerous.
The other main type of T-cells are called helper T-cells.
Helper T-cells orchestrate an immune response and play important roles in all arms of immunity.
