What are collections of similar cells called?
a. clones
b. tissues
c. organs
d. organisms

Answer : The correct answer is -

B. tissues.

Tissue can be described as the group of similar cells that are clustered together to perform specific functions.

For example- Nervous tissue is made up of nerve cells (also called neuron) that help in the transmission of electrical signals throughout the body.

Thus,option B) tissues is the right answer.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.