diff --git a/lib/tree.rb b/lib/tree.rb
index 962b72e..32c1e51 100644
--- a/lib/tree.rb
+++ b/lib/tree.rb
@@ -1,38 +1,64 @@
 class NoApplesError < StandardError; end
+class DeadTreeError < StandardError; end
 
 class Tree
-  attr_#fill_in :height, :age, :apples, :alive
+  attr_reader :height, :age, :apples, :alive
 
-  def initialize
+  DEATH_AGE = 60
+  FRUIT_AGE = 5
+
+  def initialize(height = 0, age = 0, apples = [], alive = true)
+    @height = height
+    @age = age
+    @apples = apples
+    @alive = alive
   end
 
   def age!
-  end
+    raise DeadTreeError, "This tree is dead" unless self.alive
 
-  def add_apples
+    @age += 1
+    @height += rand(2..4)
+    @alive = @age < DEATH_AGE
+
+    add_apples if @alive && @age >= FRUIT_AGE
   end
 
   def any_apples?
+    @apples.any?
   end
 
   def pick_an_apple!
     raise NoApplesError, "This tree has no apples" unless self.any_apples?
+
+    @apples.pop
   end
 
   def dead?
+    !@alive
+  end
+
+  def add_apples
+    apples_to_add = rand(10..15)
+
+    apples_to_add.times do
+      @apples << Apple.new('red', rand(1..4))
+    end
   end
 end
 
 class Fruit
   def initialize
-    has_seeds = true
+    @has_seeds = true
   end
 end
 
-class Apple <
-  attr_reader #what should go here 
+class Apple < Fruit
+  attr_reader :color, :diameter
 
   def initialize(color, diameter)
+    @color = color
+    @diameter = diameter
   end
 end
 
@@ -61,7 +87,7 @@ def tree_data
       diameter_sum += apple.diameter
     end
 
-    avg_diameter = # It's up to you to calculate the average diameter for this harvest.
+    avg_diameter = diameter_sum.to_f / basket.length
 
     puts "Year #{tree.age} Report"
     puts "Tree height: #{tree.height} feet"
diff --git a/spec/tree_spec.rb b/spec/tree_spec.rb
index b4f44c6..d43c534 100644
--- a/spec/tree_spec.rb
+++ b/spec/tree_spec.rb
@@ -5,10 +5,86 @@
   it 'should be a Class' do
     expect(described_class.is_a? Class).to eq true
   end
+
+  describe '#age!' do
+    subject { tree }
+
+    context 'new tree' do
+      let(:tree) { Tree.new }
+
+      it 'should age 1 years' do
+        tree.age!
+        expect(tree.age).to eq 1
+      end
+
+      it 'should grow at least 2 feet a year' do
+        tree.age!
+        expect(tree.height).to be >= 2
+      end
+    end
+
+    context 'a fruit bearing tree' do
+      let(:tree) { Tree.new(0, Tree::FRUIT_AGE, [], true) }
+
+      it 'should add apples every year' do
+        tree.age!
+        expect(tree.any_apples?).to eq true
+      end
+    end
+
+    context 'almost dead tree' do
+      let(:tree) { Tree.new(0, Tree::DEATH_AGE - 1, [], true) }
+
+      it "should die when it when hits #{Tree::DEATH_AGE} years old" do
+        tree.age!
+        expect(tree.dead?).to eq true
+      end
+    end
+
+    context 'a dead tree' do
+      let(:tree) { Tree.new(0, Tree::DEATH_AGE, [], false) }
+
+      it 'should throw an error if aged after tree is dead' do
+        expect { tree.age! }.to raise_error DeadTreeError
+      end
+    end
+  end
+
+  describe '#pick_an_apple!' do
+    subject { tree }
+
+    context 'tree without apples' do
+      let(:tree) { Tree.new }
+
+      it 'should throw an error' do
+        expect { tree.pick_an_apple! }.to raise_error NoApplesError
+      end
+    end
+
+    context 'tree with one apple' do
+      let(:tree) { Tree.new(0, Tree::FRUIT_AGE, [Apple.new('red', 2)], true) }
+
+      it 'should return the last apple' do
+        picked_apple = tree.pick_an_apple!
+        expect(picked_apple.color).to eq 'red'
+      end
+
+      it 'should remove the apple from the tree' do
+        tree.pick_an_apple!
+        expect(tree.any_apples?).to eq false
+      end
+    end
+  end
 end
 
-describe 'Fruit' do
+describe Fruit do
+  it 'should be a Class' do
+    expect(described_class.is_a? Class).to eq true
+  end
 end
 
-describe 'Apple' do
+describe Apple do
+  it 'should be a Class' do
+    expect(described_class.is_a? Class).to eq true
+  end
 end