B, Gases. The gases create an insulation around the planet so it keeps in heat from heat sources.
Answer:
D, think of chemical changes. When iron rusts it is chemically changed. The other answers are a change in form or a property of iron.
Answer:
The force needed to move a boy and his wheelchair with a combined mass of 30kg at 0.4 meters per square second is 12 newton.
Explanation:
- According to Newton's second law based motion "the moving object's acceleration is based upon two terms - one is the total force acting upon that object and the other one is the net mass of the object."
- In mathematical term, F=ma. where F= force, m= mass, a= acceleration.
- So, by performing the calculation,

- 12N force will move the boy along with the wheel chair.
Answer:
b. 2
Explanation:
Humans have typically 23 pairs of chromosomes. Each pair is composed of a chromosome from the mother and another from the father. A specific locus in a chromosome is composed of two alleles. An allele inherited from the mother and the other allele inherited from the father.
D. hormones would be the correct answer, which are chemical substances produced by gakbdd