Stone tools we’re first used around 3,300 BCE
Double layered nuclear, the outer nuclear membrane is continuous with the membrane of the rough endoplasmic reticulum (ER), it also continues with the inner nuclear membranes since the two layers are fused together at a numerous tiny holes called nuclear pores that perforate the nuclear enevelope
Answer: 1. Sea urchins and sea otters
2. They are prey for carnivores.
3. Sea otters, star fish
Explanation:
Sea urchins and sea otters are carnivores as they eat on the flesh of starfish and sea urchins respectively.
Starfish feed on the kelp forests which are the producers in the food chain and the starfish is the primary consumer and prey for sea urchins. So, starfish and kelp forests are the prey in the marine ecosystem.
Keystone species is the one which controls the population of other inferior species in an ecosystem. Here, sea otters consume sea urchins so the population of sea urchins remained in control Starfish controls the population of kelp forest.
The answer would be Cement,Bricks, and rock salt because in Florida they mine for hard materials
