바로 답변들어갈께요!

1. chiasma : singular /// chiasmata : plural

same thing! don't freak out.

2. Law of segregation, your explanation is spot on.

we are talking about how the offspring gets a 50:50 chance of receiving a dom. or rec. alelle

from a heterozygous parent because the two separate during meiosis.

Law of independent assortment : you're right, but you seem unsure. Let's go over it quickly.

What this law states is that what alleles I receive for one gene, has no effect on what allele I receive for another gene.

I'll try to use symbols to help you out.

Think 2 genes : Gene A (responsible for hair color) and Gene Z (responsible for toe size)

My mom is heterozygous for both traits : Aa Zz

If she creates a haploid cell, it can receive either A (dominant allele) or a (recessive allele) for gene "A"

But which "A" she gives does not determine which "Z" she gives.

(Just because she gave dominant "A", doesn't mean she has to give dominant "Z")

3. The 3:1 ratio refers to the "phenotypes" possible for crosses between heterozygous parents.

It's not related to either of the two laws you asked about.

There is one additional Mendelian Law called "Law of Dominance" 

which states that dominant alleles are expressed over recessive alleles.

Maybe that's what you were thinking about for this?

학생은 헷갈린다고 하셨는데 제가 보기엔 개념 잘 잡으신거 같은데요?

몇번 복습해야 조금 더 편안해질거 같은데

지금 개념을 이해하는데는 전혀 문제가 없고, 아주 공부 잘 하신거 같아요.

열공하시고 혹시 또 질문이 생기면 게시판에서 만나요! :D